(1) Login in to the PayPal Developer Website at https://developer.paypal.com using your PayPal login details.
(2) Click Dashboard
(3) Click Accounts on the left hand side of the page.
(4) When logging in for the first time
Two accounts are automatically created for you
If you email address is email@example.com the following accounts are made.
Customer Buyer Account
Merchant or Facilitator Account
(5) Find the personal account credit card number.
Click on the buyer email link, then
Find you Business Account Details.
Click on your facilitator email address
PayPal Pro merchants should click "Upgrade to Pro" to convert the account for a "Business Account" to a "Business Pro Account".
Find you API Credentials.
Select the API Credentials tab.
Cut and paste you username, password and signature to your PayPal Pro or Express setup.
Then select sandbox or test mode and save.
Test PayPal Express with your sandbox buyer email address and test PayPal Pro with your buyer sandbox number.
Do not use any other test number as they may not work correctly and cause and error.