Onion Skin not working for some reason

I have just started using Pencil2D today and the onion skin doesn’t seem to be working. Can someone help? Here’s a picture of the very simple animation I was working on(onion skin is on):

In the onion skin window, you have to activate onion skin, by pressing the icons under the text ‘Previous frames’ and ‘Next frames’. Then it will work

That worked! Thanks a lot!