Plz fix

I have good wifi but its really slow when I try to move something
Also when I was copying a drawing from underneath layer I turned the layer off and I couldnt draw on the layer I was copying the pic ONTO. only the linesI could draw on. I checked all my preferences and everything was good. Also I reseted it and still didnt work. Also I somehow Cant use my clear colour/eraser because it says no transparency allowed or something like that? So PLZ fix it

YuliaIsBored about Sketchbook®, v3.5.2