Lookup Table using filter to wiev average mesaure

Hello i realy need a bump with the logic in Power BI ,

I have table with average numbers with groupnames 

Databse with te details is 

I my mind i have to create a new column in my database to add my average values per group
so i was thinking filtering is good , my try just gives med the total avg not per group

So pls anyone a lite bump in the right direction 

Best regards from a Powerbi Rookie 🙂