How can I add a second internal HD

[flyheli]

I'm using a Mac mini and have two internal hard disks. It was easy to add the first one with /users/me/Music

and I can see how to add another line with the + sign but don't know how to use the correct path
The additional hard drive is named "music 750" and the subdirectory is "music" but when I enter the path
/music 750/music

I get an error message. "not an absolute path" or "not a valid file"

Any ideas how to fix this?

Thanks!