Is there some kind of idiots guide to the characters, recent plot lines etc if you’re thinking of starting to watch it?
Well, Pobol y Cwm has been around since the 1970s, so of course there is a lot of history, but I am not aware of a “newbie guide”. I suggest just jumping in, trying to note the names of a few characters and then refer to the following page for information on them (link is in Welsh):
Warning: Rabbit hole ahead
ETA: I just had a closer look, and it seems the list of characters hasn’t been updated since 2020, so the list may serve to get a closer look at the older cast, but newer characters are missing (off the top of my head, for example, the new pharmacist and her partner, Detective Delyth)
And another edit: still no newbie guide, but this Wiki seems to be more up-to-date at first glance:
This might be worth a look; Cwmderi Diary 2020 it is a fairly in-depth guide to every episode since December 2019. You might want to set a fair amount of time apart to read it though
Tony