What am I missing?

I've been having a play in WordPress but I'm finding it quite difficult to set up. I've imported all my blog posts with no problem but I can't find a theme that I like, so I've tried to pick the best and then adjust it - which is a pieceof cake in Blogger - but for the life of me I can't see how to do it in WordPress. I can find edit CSS but it doesn't seem to let me do anything.

Any help for an ignoramous please?

EDIT: OK, it seems if you want to change things in WordPress, you have to pay for the privilege. Unlike in Blogger, where you get to do all that for free. Not sure I'm going to be moving over there then.