well.. like i said, you can try beatcraft by acoustica, to me its pretty simple to use and the drum beats sound realistic enough, not those midi sounding type. If your zoom has a octave generator you can record bass using your guitar. and lastly, you just need to record your guitar.
but to record you need a mixing programme. there are some free like garageband, if you have a imac/macbook. there are other programmes like mixcraft by acoustica (i'm using this) and adobe audition.
you can record straight into your mic-in on your computer, but the sound quality will be quite bad. another alternative is to use a firewire/usb-in recording port like the line 6 toneport series. just google it and you can find out more.
hope this helps.