Blog categories in two different menu items

I am a total newbie when it comes to figuring out WordPress! I searched for my question the best I could but couldn’t find something that I could use to help me:

In writing my blogs, I want to separate them into two categories. I would like each category to be accessible through the menu on the top. I have set up both pages (body is one and mind & spirit is the second one)– how do I post actual blog posts in each page?

Thank you, thank you, thank you in advance!