Scheps 73 interface with GarageBand

I downloaded Scheps 73 plug-in as a preamp for mic recording into GarageBand. The plug-in installed and the license is active. I am not tech savvy and novice with GB. How do I launch Scheps 73? How do I get it to work with GB? Do I access the interface from GB?. In short, I just want to record my guitar with the plug-in on GB.