I would gladly appreciate all the help i have a problem with witcher 3 i instaled with disks.it instaled the GoG.when i instaled some dlc it asked me if i wanted to enter game and it work with that but when i tried to enter game through the desktop icon it said something about licence and now i don't know what to do

You need to tell us exactly what the error is, as it's shown to you. Maybe a screenshot?
If you only say "something about licence" they we have no idea what that something is.

Wait im going to instal it again so hope it will help..