Question about Book Reading

I have no clue! Never done one.
But, I would suggest the first two of book 1. Cause it might get iffy/confusing to read ch. 1 of book 2, also.
IDK. I mean, if book 1 is interesting enough, they might buy book 2 just cause it's already there. Get me?
Anyways, that's my noob-like advice and I wish you the best of luck!!

I'd say to read from the first book of the trilogy, as it seems more logical, but that's not a big point.

Pick a scene which is going to be easy for your listeners to understand--so nothing where you'll have to spend a lot of time explaining what's happening before you start to read.

Talk a little about writing, tell a funny anecdote about your writing (or writing in general) so that the audience feels relaxed and on your side. Then read for no more than fifteen minutes. Ten is better.

End at a point which is a cliff-hanger so that your audience wants to rush out and buy that book immediately, to find out what happened next.

Ask if anyone has any questions and if so, answer them as honestly as you can. If you don't know the answer to a question say so (but perhaps offer to find out and get back to the person later). Don't try to pretend, it doesn't work.

And remember to breathe!

Nothing to add other than good luck.