Step 1: You need a credit card or bank account you can use to get money from. Make sure you have one.
Step 2: go to www.paypal.com
Step 3: Hit Sign up.
Step 4: Chose your type. Most people do Personal unless you plan on selling things.
Step 5: Enter all the iformation into the page.
Step 6: Validate your account threw your e-mail.
Step 7: If you use credit it's simple. Enter your information, and your done and ready to buy things. I'm not so sure about the bank option, but Mike Briant may be able to help you with it because I believe he uses it.