Adding Mono File to Stereo File

I have some music I purchased through Music Bakery that is in Stereo. When I try copy and paste it into an mp3 recording I have which is mono, it says I can’t do that. How can I combine these two.

Assuming you want to keep the stereo of the purchased file, click above Mute / Solo of the recording track to select it and Edit > Duplicate.

If the bakery song is now between the two recording tracks, use the Audio Track Dropdown Menu on the upper of the two recorded tracks and choose “Move Track Down”.

On the upper of the two recording tracks, use the same dropdown menu and choose “Make Stereo Track”. Now you can paste the bakery song into the recording.