So you are wondering what is canon and what inst well you come to the right place.
What is canon
1. star wars saga
2.clone wars and The clone wars
3.star wars rebels
4.Any comics that are not branded legend
I may have mist something but this is the main list of canon star wars.
The resewn why Disney said what is canon and stuff that inst is because of the new star wars episode 7 and the new trilateral.