Self host, 2nd WP blog install question

I did look but didn’t see an answer to this question:
On my domain I have one wp blog at mydomain.com, I want to make a second blog on the same domain with a different name so I created a directory, mydomain.com/blog to install it. The prob is the 2nd blog keeps inheriting the 1st blogs name (which is the domain name) instead of the different one I want to use. What am I doing wrong? I did it a long time ago but since deleted blog 2 and cannot remember how I got the 2nd blog to have a diff name.

Stumped