How to change your level?

I’ve chosen level Beginner 1 and I’ve noticed that it’s too easy for me. how do I change my level?

If you mean the Lessons in the Library, there’s a down-arrow next to where it says “Beginner 1” on the left of the Library screen. Hover the mouse over the down-arrow, and after a second you’ll get a menu where you can change your Library to Beginner 2 etc for more difficult lessons.