how to go back to a previous grease pencil frame? so when using grease pencil it gives the option to add a frame, however once a Frame has been added how do I go back to the previous frame? EG; on frame 1 I drew some vertical lines, then selected new frame and drew some horizontal lines but how do I get back to the vertical ones? 
difficult to explain but I hope u understand the question and can give me an answer XO
Just click on the timeline frame 1.This is the most simplest method. Hope it helps!