How use gem Cancan on Rails

I have read a lot of website tutorial Cancan gem, but I can't understand it. I want to create, edit role, and add user to role. config premiss for role. etc...

You are probably better going with the cancancan gem which follows on from cancan. Instructions for using it can be found at [1]. If there is anything there you do not understand then come back and ask specific questions.

Colin

[1] GitHub - CanCanCommunity/cancancan: The authorization Gem for Ruby on Rails.