Enter an API user name you've obtained from PayPal
Enter an API password you've obtained from PayPal
Enter the PayPal gateway. Usually, https://api-3t.paypal.com/nvp
Client Side SSL
Select this option if you are using a certificate.
Select this option if you are using a signature.
Signature for 3-token Authentication
Password of the Certificate file for Client Side SSL
Full file path of Certificate file for Client Side SSL.
Click this to check the connection to the gateway using the credentials provided.