afish, and suzannahj: well done with your progress so far. The preamble can be tricky to unpick, as it tries to pack a lot of detail into a few words. Some weeks you will find considerable discussion on here as to exactly what the preamble meant! But many of the things it mentions (clashes, cycles, misprints, etc) will become familiar as you do a few of these, and they’re well worth the effort to learn.
afish, I would say that referring to Chambers is absolutely vital. Even if you have a huuuge knowledge of obscure words — and the setters love to find the most obscure! — the clues sometimes reflect specifics of how Chambers defines a word, so a clue that is mysterious becomes suddenly clear when you look up the Chambers definition of a key word.
29a is the abbreviation, and a well known one. “Who may save”, it says, and if you manage a post-lockdown trip to the seaside stay safe so they don’t end up having to save you!
If you’ve got the misprint message, take it literally. What do you have for the clue that’s mentioned? And what was on its reverse? Actually on the reverse. Google it if it’s not in your record collection. Then trace those fifteen letters through the clash cells — it’ll sometimes use the letter from the across clue and sometimes from the down clue — starting in the TL quadrant then TR then BL then BR and you’ll have written out some handy big letters. The *other* choices at all the clashes spell an entirely different form of the thing that can also be covered by and entirely different form of what the big letters spell out! It’s worth persevering because the satisfaction from finishing one of these is considerable :-)