You need to do what many of us have already done, some homework.
First, check all the stuff on PayPal's main web site as it has and explains the basics of getting started.
Next, visit this page, there you can learn about the various types of item button code that can be used on a web page or converted into text or hyperlinks.
Also check out the two user guides listed below, both can be found here.
Merchant Setup and Administration Guide
Website Payments Standard Integration Guide
And you can find some Tutorials here.
Regards,
skier
