Zen Cart / PayPal questions

Right now, I'm using Zen Cart 1.3.9h, and PayPal Website Payments Standard.

I also have the store pickup changed to have two different pick up locations, and I want to add descriptions to each, stating things like the address, time allowed to pickup and other things. How can I do this?

Also, How exactly does the whole thing work, they checkout, pay through PayPal (or credit card), I get notified with an invoice, the get an email receipt/invoice, and then they pick it up?

With regards to this, how do I edit the email they get, and is it zen cart or paypal that sends the email, because I want to have separate directions for each shipping location. Is it automated or do I have to send each email individually?

Lots of questions, I know,