Thanks for the comments
@Ben J. I tried doing that with migration assistant. It did not seem possible to specify just the folder which contains only my documents. Migration Assistant wanted to transfer all sorts of other file types and other folders too.
I had owned my old MacBook for ten years. I feel a fresh start was probably better than carrying over all the detritus that a computer picks up over that period of time.
What I considered doing was to copy all my documents from my old Mac’s hard drive to an external hard drive and then copy those from there onto the new Macbook.
That seems a somewhat roundabout way of doing what I wanted when I have a Time Machine backup.
Anyway, it’s done now. I just hope I’ve captured it all.
Later today I’m going to copy (not TM backup) all the files from my old MacBook onto another external drive. I will then have a snapshot of all my documents just in case. Belt and braces!