complicated - not sure how to describe this - blog questions

The whole blog thing is really a concept I don't understand. On my old site we had some testimonial blogs, which we categorized as 'testimonals' (I don't even know how we did that) and they showed up on a testimonials page. I would like to replace the dropdown menu item welcome>clinical testimonials with the blog of testimonials and copy the testimonials from 'clinical testimonials' over to the blog. In essence, I want to merge the files into a blog dedicated to testimonials. How can we make this happen?

I need to have a second blog - welcome>why I do this> a day in my life. This is one people often leave comments on - but I don't see a way for them to leave comments as it is now. How do we set up 2 blogs on one site, both with room for visitors to leave comments?