Not able to record

Hi - Can anybody give me some advice …. I have my UR44 ready to go, using it with a microphone, wanting to record singing in Garageband on my Mac computer. But it is not recording. I know the record function is working fine on my computer because just a while ago I recorded some stuff using just a simple USB microphone. Now I’d like a better sound so want to use my better microphone and the UR44 interface. I suspect there’s something minor that I don’t have turned on or adjusted properly or whatever, but I cannot figure it out. Any suggestions from anybody ??