Help for Aimeos

There are so many docs here and there. Which is the single source of docs which I can follow to understand this aimeos e-commerce. For example I can't find anywhere what does Stocks mean. I can't get how to assign permissions to my custom user groups.

I went through the guideline to install the aimeos as a new fresh application to test and learn.

https://github.com/aimeos/aimeos

The composer command to install this package installs lararvel 6. I tried to change composer.json for laravel 8, but then as suspected other dependencies error start ...