add sidebar menu and delete top menu

I’m a total newbie and, although I’ve got my site up and running (http://tarotmeister.com) there are some things I just can’t figure out, starting with…
1. I want to get my sidebar menu on all my pages and delete the big distracting top menu. How?
2. I want to get rid of the big “comments” box at the end of every page but the homepage. How?
3. I don’t understand how to add child pages.
If the answers to these questions involve changing html or php codes please start at the very beginning. I don’t even know how to get there to change things.
I’d appreciate any help I can get. Thanks, Gary