Create a multi starter

Hmmm... ok.
So, lets say you want to launch Firefox and the Gimp at the same time (just for an example).

1) create the script file named: [whatever].sh
in this case: firegimp.sh

2) open up that file with a text editor of your choice and as your first line put the "hash-bang":
#! /usr/bin/env bash

3) Now we can enter bash shell commands untill our fingers blister. You can test these in real time by running them in the Terminal (Applications>Accessories>Terminal). Here, we will separate the names of the programs or commands we are running with " & " so that each command/program is (essentially) launched at the same time. For firegimp.sh we would have:
firefox & gimp

* So, just to check, the file firegimp.sh should look like this:

#! /usr/bin/env bash
firefox & gimp

4) Now save and close the file. And we need to give it permission to behave like a program, so, right-click on the file and select "Properties"; now go to the "Permissions" tab; and then check the box that says something along the lines of 'allow file to execute as program'...

You should now be able to double click on the script and have Firefox and the Gimp launch at the same time (oh, joy).

I hope this helps.
Read more at https://help.ubuntu.com/community/Beginners/BashScripting . You can also find loads more by googling something like "intro to bash scripting".