iMovie can't drag videos down to timeline

I have seen this in other questions but with no solution. I am trying to combine multiple QuickTime movies I have into 1. they are about 40 min long each. They have audio and video, I import them into iMovie but then always get the following error message "you are combing audio and video clips outside the primary storyline. You cannot add video clips to existing audio only compound clips".

This makes no sense to me. I have searched the net for a solution and have found none. I have qt movies that have audio already and am only trying to combine them. nothing fancy here. I have opened a project. No where does it indicate that I have an audio only project and all my clips are just movies with sound so where is there an audio only clip? I am completely lost here and stuck. I have never used iMovie before because have always gotten this message and then just quit and given up but this time I want to make this work. oh, I am using MacOS Monterey and iMovie version 10.3.5. Please advise. thanks!