Unfortunately those are not the instructions Apple has for opening a library on another drive. Those are for re-assigning where just media (which is not the totality of your library) are stored.
To open the library you need to start iTunes and immediately hold down the option key. When it asks you where the library is located, show it the one on the second drive.
Hopefully re-assigning the media folder location has not made a mess of things.
The secondary drive that contains the iTunes data does not have a "library" item on it. It simply contains two folders, "Desktop" (which is empty) and "iTunes Media" which contains all the folders that make up the iTunes media.
However, there is a "iTunes Library.itl" file in Music/iTunes on the old boot hard drive that was replaced by the SSD. Chosing that library when starting up iTunes with the option key down does seem to fix the problem.
However, this is odd in that now three different drives are involved in this process– the boot SSD, the old boot HD, and the secondary drive that is dedicated to the iTunes media. I wonder if I could just copy the "iTunes.Library.itl" file from the old boot drive to the drive that contains all of the iTunes media?