I just joined this website...thingy and i dont know how to erase things. I found out that there is a undo button, but that doesnt help when im sketching anime and need to draw the circle and then the upsidedown triangle beneath it to get a good shape. Some lines i just dont need anymore and need to get rid of without deleting the lines before it. Can somebody please help me?

You mean you want to erase the whole thing from the guide lines? Well, it's easy. Because you can just click the eye button next to the word 'sketch', and then the guide lines will not be shown.

But if you want to erase the linearts and the colors, you can just actually use the pencil tool, and the color white, to erase these things.

if youn wanna erase em, just click pencil then changeb the color to white.. sore dakede ii...

Change your pencil color to WHITE