Narration is mostly added as slide audio. You can have Background audio in the project as well, although it can be very confusing for the learner. At least lower the volume of the background audio, which is possible.
Thank you Lilybiri.
May i please request you to detail the steps to add the same (if possible)? It would really be helpful.
Although, I must mention that I have added TTS narration already and want to add BGM.
Thank you again.
Menu Audio, Import to Background, or if you want Record to Background. You could also import the audio first to the Library.