Selecting different parts of clip for multicam
I'm trying to create a multicam clip from 5 cameras plus sound. I used to be able to do this and now I can't (in v 10.6.1.) .The cameras produce files of different length so the clips do not quite cover the same time. I select the part of each clip that I want by simply highlighting with In and Out. I use the sound for synch, and that is a single track of 65 minutes, so I need to cut it.
How can I now select these areas in each clip to create a new multicam clip? I'm sure I just used to Command/left click each one in turn to build up a list.
Can't find any YouTube help as they all seem assume that I will use the whole of the clip, not part.
Any ideas?
iMac 27″, macOS 11.3