To get everyone in the Holiday spirit, let's create a Christmas track in Reaper. I'm going to attempt Deck The Halls. To fast track things, I'm going to find a freely available MIDI version of the track, from there I'll assign virtual instruments to the MIDI tracks. I'll also show you how to import loops into Reaper and timestretch them so that they fit to the rest of the elements in the arrangement.
Step 1 '" Deck The MIDI
I found a good MIDI version of Deck The Halls at Rob's MIDI Library X. To get an idea of the track, you can preview it through Quicktime. Quicktime is a handy app to preview MIDI files through as it will replay them using the Quicktime MIDI Synth instrument. Now to get it into Reaper'