I hate to say this but it is all in the manual.
You need to go into your preferences and assign an audio driver for starters
I have been using DAWS since Pro-Tools 1.1 and this application took me a couple of years to get comfortable with. I was reading the manual all the time. One of the things that might help is that audio objects need to be in rec mode to pass audio from external devices as well as through MIDI. At first Logic seems illogical but once you get into it it is well worth the learning curve.
You are not going to be able to use it like Garageband you are going to have to work at it to get into it.
Good luck and don't look back.
Daniel R. Shattuck
http://www.ipeace.tv