Broke my site by trying to get the URL to lead somewhere else

I am in the process of slowly converting addressmunger.com into wordpress. The current location is at addressmunger.com/articles/

I wanted the following
* pages to appear to be located at the root folder, addressmunger.com/
* blog posts to be located at addressmunger.com/articles/

I went to just change the text at the general settings to https://www.addressmunger.com , but that actually broke the entire blog.

I then went to this site to find a solution:
https://codex.www.ads-software.com/Changing_The_Site_URL

I used the file functions.php as they recommended, but now I can’t seem to change any of those settings. I want to reset all of that, so I can do what it is I wanted to do. I am stuck. I don’t know what to do.