1st Step
If you already have a PayPal account, get the email with PayPal
or
Create your PayPal account through the link http://www.paypal.com
2nd Step
After obtaining the email of registration with PayPal
Access the control panel of your store
After login click Modules >> Payment >> Select PayPal or MODULE_PAYMENT_PAYPAL >> Click the INSTALL / EDIT button
Fill in the E-Mail Address field (the other options are not mandatory) and click the UPDATE button