Also, the one directory site I attempted once was a pain to get set up. I think to do it justice, one would need to do a lot more research than I had time for, to have the quality I was aiming for.

I mentioned in my previous post that I'm interested in creating a directory site.

I have to be honest. I don't know where to start. First, I have to buy a domain. Do I insert a directory script after that? And then what? I hope somebody can help me with this.

I think you can get directory scripts for free also.
check php.resourceindex.com
Once you installed the script then you can easily to anything through the admin panel.