@40Jem
I've never read any of them . What would you recommend to read first?
You don't need to read the whole series in the order in which they were written. They split into several themes and a few standalones so I'd start at the beginning of a theme, read the rest of the books in the theme and then, if you like them, start at the beginning of the series. The most popular themes are the witches, the Watch and Death.
Witches: Wyrd Sisters, Witches Abroad, Lords and Ladies, Masquerade and Carpe Jugulum. Equal Rites comes at the beginning of this theme but it's not a great introduction because he hadn't really got into his stride yet.
The Watch: Guards! Guards!, Men at Arms, Feet of Clay, Jingo, The Fifth Elephant, Night Watch, Thud! and Snuff.
Death: Mort, Reaper Man, Soul Music, Hogfather, Thief of Time.
Be aware that the Alzheimer's starts to show before the end of the series. IMO he got a bit clunky with the messages in the last books and The Shepherd's Crown is best left unread so you never finish all his books.
GNU pTerry.