Finally got back home and AppStore categorically says new downloads of iMovie require OS 12.6 or later and Pages requires 12.3 or later.
The download pages for iMovie and Pages recognize the version of the Mac OS you are running and automatically offer the proper version. However, you have an old computer that Apple considers to be "obsolete",
https://support.apple.com/en-us/HT201624
and I don't know, but it may be that because Apple no longer supports obsolete Macs that they don't automatically offer a version of iMovie or Pages that will run for you.
I have searched online and can't even find older version downloads.
You can download all of the past versions of iMovie from:
https://support.apple.com/downloads/iMovie
You can download all of the past versions of Pages from:
https://support.apple.com/downloads/Pages
Not the end of the world as I've now downloaded PowerDirector 365
You might also want to have a look at:
Openshot Video Editor (free)
https://www.openshot.org
Shotcut (free)
https://shotcut.org/
Davinci Resolve (free; commercial "Studio" version has more features)
https://www.blackmagicdesign.com/products/davinciresolve/
https://apps.apple.com/us/app/davinci-resolve/id571213070?mt=12
(Professional video editing, color correction, audio post and visual effects!)
and followed your suggestion and I am giving Free Office a go.
Great! Please let us know how you like it.
It would also be interesting to hear if you get an e-mail in the next week or so offering you a special deal on Softmaker Office, and how much they want to charge for it.
I started using Apple over 20 yrs ago because I felt at the time that Microsoft was letting me down and I hate to say it but I am starting to feel the same way with Apple. Nothing is straightforward any more.
I know how you feel. Technology keeps on moving forward, and it's a bit of a slog to keep up with it. But the good news is that if there is anything that you aren't caught up with, you can just ask about it here.
Thanks a lot for your help and I will be keeping my eye on your free software link.
I just added four new products to the page last night! In fact, all four were very exciting. I'll post about them elsewhere on this forum.