How to customize how comments are displayed

Hey, its me again. My site is modernrevolutions.net and I was wondering how to customize my comments section. I would also like to know how to fix this overflow problem I am having with my comments. if you go to one of my blog posts and click the “# Comments” link and scroll down as if to comment on my blog, you will see that for some reason you can now scroll to the right alot. Why is that? Thanks!