Blog:Changing the site's design back to what it was

Recently, Miraheze just got an update which changed the layout for all of its wikis, and I don't like it, so I want it to look how it was before.

Does anyone know how to change it back? I clicked on "Switch to old look", but then came this menu of complicated shit which I have no idea how to use, so I'm wondering if anyone can give me a tutorial on how to change the wikis' layouts back to normal.