Question on showering and gridpack run

Hello,
I'd like to have a clarification about showering when using gridpack. I produced a gridpack with my process following the instruction reported in [0] and [1] i.e:

define j = j b b~
generate b g > w- t, ( t > w+ b , w+ > l+ vl )
add process b~ g > w+ t~, (t~ > w- b~, w- > l- vl~)
add process b g > w- t j, ( t > w+ b , w+ > l+ vl )
add process b~ g > w+ t~ j, (t~ > w- b~, w- > l- vl~)
output PROC_TW_03_tw1j
Then I exit mg5 interactive session, turned gridpack on in PROC_TW_03_tw1j/Cards/run_card.dat
  True = gridpack !True = setting up the grid pack
and finally
./bin/generate_events
Here, when asked, i set shower to Pythia8:
/=================== Description ===================|============= values ==============|======== other options ========\
| 1. Choose the shower/hadronization program | shower = Pythia8 | OFF |
| 2. Choose the detector simulation program | detector = Not Avail. | Please install module |
| 3. Choose an analysis package (plot/convert) | analysis = Not Avail. | Please install module |
| 4. Decay onshell particles | madspin = OFF | ON|onshell|full |
| 5. Add weights to events for new hypp. | reweight = OFF | ON |
\=======================================================================================================================/

hit return a couple of times and everything seems ok. I got my gridpack (see [2] for the full generate_events output) and tried to generate few events...
I copied the gridpack file in another directory, untarred it and run the script run.sh for 10 events.
Everything looks ok but the events are not showered and I see only the hard scattering particles.

So my questions are:
1) Is this the normal behaviour and I need to shower by myself the LHE events? (how? Is this something included in the mg5_amcnlo package?)
2) If not, what am I missing? How can i produce a gridpack which run the showering step?

Thanks for helping

Attilio

[0] https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/GridDevelopment

[1] https://indico.cern.ch/event/555228/sessions/203428/attachments/1315471/1970459/tutorial-CMSandATLAS-2016.pdf slide 61

[2] Here is the output of the generate_events command:
bin/generate_events
************************************************************
* *
* W E L C O M E to *
* M A D G R A P H 5 _ a M C @ N L O *
* M A D E V E N T *
* *
* * * *
* * * * * *
* * * * * 5 * * * * *
* * * * * *
* * * *
* *
* VERSION 3.5.1 *
* *
* The MadGraph5_aMC@NLO Development Team - Find us at *
* https://server06.fynu.ucl.ac.be/projects/madgraph *
* *
* Type 'help' for in-line help. *
* *
************************************************************
INFO: load configuration from /lustre/home/santocch/2022.06.12.finalAnalysis/DELPHES/MG5_aMC_v3_5_1/PROC_TW_04_tw1j/Cards/me5_configuration.txt
INFO: load configuration from /lustre/home/santocch/2022.06.12.finalAnalysis/DELPHES/MG5_aMC_v3_5_1/input/mg5_configuration.txt
INFO: load configuration from /lustre/home/santocch/2022.06.12.finalAnalysis/DELPHES/MG5_aMC_v3_5_1/PROC_TW_04_tw1j/Cards/me5_configuration.txt
No valid text editor found. Please set in ./input/mg5_configuration.txt
No valid eps viewer found. Please set in ./input/mg5_configuration.txt
No valid web browser found. Please set in ./input/mg5_configuration.txt
generate_events
The following switches determine which programs are run:
/=================== Description ===================|============= values ==============|======== other options ========\
| 1. Choose the shower/hadronization program | shower = OFF | Pythia8 |
| 2. Choose the detector simulation program | detector = Not Avail. | Please install module |
| 3. Choose an analysis package (plot/convert) | analysis = Not Avail. | Please install module |
| 4. Decay onshell particles | madspin = OFF | ON|onshell|full |
| 5. Add weights to events for new hypp. | reweight = OFF | ON |
\=======================================================================================================================/
Either type the switch number (1 to 5) to change its setting,
Set any switch explicitly (e.g. type 'shower=Pythia8' at the prompt)
Type 'help' for the list of all valid option
Type '0', 'auto', 'done' or just press enter when you are done.[60s to answer]
>1
The following switches determine which programs are run:
/=================== Description ===================|============= values ==============|======== other options ========\
| 1. Choose the shower/hadronization program | shower = Pythia8 | OFF |
| 2. Choose the detector simulation program | detector = Not Avail. | Please install module |
| 3. Choose an analysis package (plot/convert) | analysis = Not Avail. | Please install module |
| 4. Decay onshell particles | madspin = OFF | ON|onshell|full |
| 5. Add weights to events for new hypp. | reweight = OFF | ON |
\=======================================================================================================================/
Either type the switch number (1 to 5) to change its setting,
Set any switch explicitly (e.g. type 'shower=OFF' at the prompt)
Type 'help' for the list of all valid option
Type '0', 'auto', 'done' or just press enter when you are done.
>
Do you want to edit a card (press enter to bypass editing)?
/------------------------------------------------------------\
| 1. param : param_card.dat |
| 2. run : run_card.dat |
| 3. pythia8 : pythia8_card.dat |
\------------------------------------------------------------/
 you can also
   - enter the path to a valid card or banner.
   - use the 'set' command to modify a parameter directly.
     The set option works only for param_card and run_card.
     Type 'help set' for more information on this command.
   - call an external program (ASperGE/MadWidth/...).
     Type 'help' for the list of available command
 [0, done, 1, param, 2, run, 3, pythia8, enter path][90s to answer]
>2
open /lustre/home/santocch/2022.06.12.finalAnalysis/DELPHES/MG5_aMC_v3_5_1/PROC_TW_04_tw1j/Cards/run_card.dat
Not able to open file /lustre/home/santocch/2022.06.12.finalAnalysis/DELPHES/MG5_aMC_v3_5_1/PROC_TW_04_tw1j/Cards/run_card.dat since no program configured.Please set one in ./input/mg5_configuration.txt
Are you really that fast? If you are using an editor that returns directly. Please confirm that you have finised to edit the file[y] [60s to answer]
>
Do you want to edit a card (press enter to bypass editing)?
/------------------------------------------------------------\
| 1. param : param_card.dat |
| 2. run : run_card.dat |
| 3. pythia8 : pythia8_card.dat |
\------------------------------------------------------------/
 you can also
   - enter the path to a valid card or banner.
   - use the 'set' command to modify a parameter directly.
     The set option works only for param_card and run_card.
     Type 'help set' for more information on this command.
   - call an external program (ASperGE/MadWidth/...).
     Type 'help' for the list of available command
 [0, done, 1, param, 2, run, 3, pythia8, enter path]
>
INFO: Update the dependent parameter of the param_card.dat
WARNING: update the strong coupling value (alpha_s) to the value from the pdf selected: 0.13
Generating gridpack with run name run_01
survey run_01 --accuracy=0.01 --points=2000 --iterations=8 --gridpack=.true.
INFO: compile directory
Not able to open file /lustre/home/santocch/2022.06.12.finalAnalysis/DELPHES/MG5_aMC_v3_5_1/PROC_TW_04_tw1j/crossx.html since no program configured.Please set one in ./input/mg5_configuration.txt
compile Source Directory
Using random number seed offset = 21
INFO: Running Survey
Creating Jobs
Working on SubProcesses
INFO: Compiling for process 1/4.
INFO: P3_bg_wmtg_t_wpb_wp_lvl
INFO: Compiling for process 2/4.
INFO: P4_bxg_wptxg_tx_wmbx_wm_lvl
INFO: Compiling for process 3/4.
INFO: P1_bg_wmt_t_wpb_wp_lvl
INFO: Compiling for process 4/4.
INFO: P2_bxg_wptx_tx_wmbx_wm_lvl
INFO: P3_bg_wmtg_t_wpb_wp_lvl
INFO: P4_bxg_wptxg_tx_wmbx_wm_lvl
INFO: P1_bg_wmt_t_wpb_wp_lvl
INFO: P2_bxg_wptx_tx_wmbx_wm_lvl
INFO: Idle: 1, Running: 13, Completed: 10 [ current time: 11h06 ]
INFO: Idle: 0, Running: 14, Completed: 10 [ current time: 11h06 ]
INFO: Idle: 0, Running: 9, Completed: 15 [ 3.4s ]
INFO: Idle: 0, Running: 5, Completed: 19 [ 6.4s ]
INFO: Idle: 0, Running: 4, Completed: 20 [ 9.6s ]
INFO: Idle: 0, Running: 3, Completed: 21 [ 26.2s ]
INFO: Idle: 0, Running: 2, Completed: 22 [ 35.2s ]
INFO: Idle: 0, Running: 0, Completed: 24 [ 55.4s ]
INFO: Idle: 0, Running: 0, Completed: 24 [ 55.4s ]
sum of cpu time of last step: 4m39s
  === Results Summary for run: run_01 tag: tag_1 ===

     Cross-section : 8.371 +- 0.0308 pb
     Nb of events : 0

INFO: End survey
combine_events
INFO: Combining Events
store_events
INFO: Storing parton level results
INFO: End Parton
decay_events -from_cards
create_gridpack
INFO: Creating gridpack
P3_bg_wmtg_t_wpb_wp_lvl
P4_bxg_wptxg_tx_wmbx_wm_lvl
P1_bg_wmt_t_wpb_wp_lvl
P2_bxg_wptx_tx_wmbx_wm_lvl
Cleaning SubProcesses....
INFO: gridpack created
quit
INFO: storing files of previous run
INFO: Done
INFO: