Help with channels

I recently made some karaoke for my musical theater group for speech. I used a computer and keyboard and recorded the song and converted it to an mp3… however i only had a left channel… no right… so i want to copy the left onto the right so it is louder… can i do this and how?

Select the song. Duplicate (Edit > Duplicate).

Drop-down menu from the top channel > Make Stereo Track.

If the goal is just to make it louder, you might try Select the track > Effect > Amplify new peak to -1dB > OK.