A Little Help, Please.

That impression would be correct. As long as you have a vsti that makes the sounds you want. There's heaps of free ones out there (or Reason can be rewired to reaper to produce the sound given midi - but I don't own reason, so can't help you there). What sort of sound are you looking for, and are you already trying to send your midi to a vsti? You don't mention that.

Also, here's a great thread with heaps of great sounding free virtual instruments and fx.

if you have midi data on a track, you need to send it to some sound generating device (hardware or software - you're planning on using all software). The quick/easy way of doing this is to load your sampletank vsti into the fx on your midi track. Your midi data will be sent through the fx chain, and your sampletank vsti will pick this up, play whatever it's asked to play, and generate sound. If you want to generate a wav file (once you've got it making sound), you can use the file/render to do this (for your entire mix) or just to bounce down the midi/fx track you can right click on the track panel and select 'render selected tracks to stem tracks' which will create a wav (from the midi/fx combo) and stick it on a new track.