License for second computer

I purchased MIDI Guitar for my iMac desktop, now wish to put it on my MacBook. I downloaded it again from the App store, but the download is now asking me to purchase the full version again. How do I transfer the license to the MacBook? (I want to use it on both machines)

Also, I don’t see any evidence of a MIDIBass, which I would like very much to use. Do I have it, or how do I get it?

If you have bought “MIDI Guitar for Garageband” in the appstore, the license is bound to your apple id.
Go to the shop inside our app, and click “restore purchase”. You should login with the same apple id which you used for your original purchase.