Star schema performance

I am trying to creating to star schema of existing tables which is in power bi .. 

i am trying to create with the help of this tutorial https://www.red-gate.com/simple-talk/sql/bi/power-bi-data-modelling/

So when i am trying to create fact table then there is to much loading .. what should i do ?

 is creating star scehma is better approch in power bi ?

when we create star scehma then performace issues should be better or not ?

Kindy guide