One question I forgot to ask him was what powers the CD/MP3 player that goes in the little box on side. I don't see any AC type connection. Is it only batteries?
Yes - Batteries. The unit comes with an AC adapter, but there's really no way to run the wire for it. The good news: you will using the line out, not the headphone out, so the unit 'sips' at the batteries instead of sucking them dry quickly.
Also, I forgot to ask him to tune in some FM stations, so I don't even know where and how that is done.
Just switch to FM, and start tuning. The reception is not all that strong, and there's a reason: many of these units use the wire to the headphone as part of the antenna. Since you won't have the headphones plugged in, you may not get all the stations you would like. I haven't tried plugging in the headphones, or substituting a simple wire in a mini-plug, but I suppose it could be done if you can't get the station you want. They do ship a set of headphones with the units, so you can experiment easily.
The FM receiver works just fine for what I need: to receive signal from an FM transmitter in my house, connected to the stereo/ home theater. The rest of the time I run mp3 files that I burn (leagally) from my computer and a large collection of audio CDs. You can fit close to ten hours of music, in mp3 format, on a single disc.