Hi All - It's been awhile, but I've just got back into editing and thought I should close by saying -
I now understand the "create nest" action that Stephen was talking about in post 7. Yes you are right, they work just the same as subclips and I can apply effects (which was my original target action) to nests created this way.
Re Posts 4 & 8 - just a terminology issue. I was wanting to keep the original multiple media tracks visible (in my case multiple audio tracks and single video track which I had pre-synced in PluralEyes before import) and was finding they were all joined up into a single sequence bar. But after a few more searches, found the toggle that allows you to Insert and Overwrite sequences as nests - which made the original tracks individually visible.
Stephen - Thanks for your patience to help me work through this.