i cant figure out how to defrag my computer

i need to figure out how to defrag my computer i am new to ubuntu. my computer saves everything to my home folder and then to another folder it is filling up my hard drive and making my computer run very poorly

It is normal to save things to your home folder, this is where all of your user-specific items end up. What other folder is it saving things into? If your drive is filling up it needs cleaned out, not defragmented.

In general the linux filesystem does not need defragmenting. Many of them do not even have the tools to do so.

You never have to defrag ext3 or ext4. The journal tells the system where to find the data and keeps the data well. The system also recognises that data access is fragmented so 100% contiguous files will actually slow down the system. All you have to worry about is leaving at least 10% free space on each partition.

The default is to save everything to your home folder, that is where user data is to be stored. It is synonymous with the windows "My Documents" folder so this is completely normal.

You can save space by running:

sudo apt-get clean

in a terminal to clear the old .deb files out from updates and installs of programs. You can also clear out your web browser cache.

If you want to analyse your system performance run:

top

in a terminal and watch what happens. Watch CPU and RAM usage of the apps.

Can you also provide:

system cpu speed
system ram amount

and the output of:

df -h

Thanks