I am planning to sell some ebooks but I don't know how to add the ebooks to my site in dreamwaeverMX. That way after they pay for the book, they can be directed to a link where they can download the book. How do I set this up on my site?

Look at PayPal's Instant Payment Notification (IPN). It makes a callback to your server once the payment has been completed so you can give the user access to the eBook.

You will most likely need server side code to provide the authentication as to if the user has paid or not, to prevent people bypassing the payment and downloading it directly.

And where do I get this code? By the way, thanks for your reply.

from PayPal

THANX