Place your mono track on the timeline. Render it to a new stereo file. There won't be any real benefit though as anywhere the mono file is used in stereo output, the signal will appear in both channels.
Since you are a newbie, this may be a bit complicated, BUT...
Use the WaveHammer plugin on your file, and look through the various impulse files available. In many cases, there will be a "simulate stereo" choice. I have used this a few times and it doesn't sound bad as long as you were going to use some reverb effect anyway. The simulation of stereo is actually (in this case) just having slightly different reverb effects on each of the two channels.