Replacing audio in video

I’m new to video, making simple recordings of live performances of fellow musicians. I am having a very difficult time replacing audio in a video file. When exporting the edited audio mixdown, I am at a loss as to what specifications I should use to make the mixdown track function when it replaces the original sound track in the video. Any recommendations, referrals to good information sources, would be appreciated. I was able to succeed one time out of many attempts, but failed to make note of exactly which format options I selected. The replacement operation always appears to succeed, but playback fails. Is there a reliable combination of audio and video formats, ie MOV, AVI, whatever, that would produce reasonable results without being overly complex?