According to the docs the UMC22 is class-compliant, so it shouldn't need a driver, it should be plug & play. It should show up in GB Preferences > Audio/MIDI > Devices under input & output. If it doesn't show up there, check the Mac utility Audio MIDI Setup [Applications > Utilities] to make sure the computer sees it.
If it does show up but you don't see/hear incoming audio, make sure you have the appropriate input selected on an Audio track in the Smart Controls panel at the bottom [shortcut "B"] under Track > Recording Settings > Input, and enable the Monitoring button to hear the incoming audio before you start recording.
I've attached a GB course at the top [click "More Info"] -- video # 4 discusses setting up hardware, maybe there'll be something helpful in there..
Re "it reads it as USB Audio Codec".. see the next post..