The steps to turn paypal on at your site are as follows:
1. Go to the store settings link
2. Turn off the 'forcecc' option if it is on. This will allow a consumer to click paypal on the checkout page, and NOT enter a credit card.
3. In the field storecc, you will see some radio button html code for what credit cards you can accept. Add this: PayPal
4. Lastly, hit 'save' at the top of the screen.
You will see that Paypal is an option on the checkout page. There is also a link that explains how to pay via paypal for the consumer. When the transactions come through they will be marked PAYPAL. You should immediately go to Paypal and confirm that everything matches up ok.