Post on Multiple Webpages

I’m trying to do some research on WordPress and how it works internally so that I can set up a website for myself.

Let’s say I won domain.com, and have wordpress installed in a subfolder called “blog”. Visiting domain.com will bring you to the index.html page stored on my server, which is not managed by WordPress, but going to domain.com/blog will bring you to the blog that is managed by wordpress.

After logging into WordPress, I can easily create new posts which will appear on domain.com/blog, but what if I wanted to make a post that will appear on, say, domain.com/blog/otherblog? I know I can create a new page and have it permalink as “otherblog”, but when I make new posts they won’t show up there, they only show up on the home page. Is there a way to make posts such that I can choose which page they show up on?

If I want to separate posts completely, will I need to have more than one installation of WordPress in the different directories?