something I had to figure out was it's very picky about the connection between frames and layers. Essentially there needs to be a layer with the samen ame as a frame (usually jsut a number)

and like so clicking betwene the layers also changes the frame you're on. If you want to make new layers in there or merge stuff down all for the sake of drawign then you'll need to move the layer out of the animation folder first. in fact you could make a new frame, delete the layer it creates with it, and then rename another layer with the same number, move it in its place, and boom that works haha.