Select this option if the PayPal account is a Sandbox account. A Sandbox account is used to test the process of payment before using the real account. You can check out this website https://developer.paypal.com.
Encrypt the payment details. In order to do this, you must have a PayPal account and you need to upload a public certificate to PayPal and get a certificate ID in return. Use the PayPal Encryption Key Manager to generate a public certificate to upload to PayPal. A form for submitting payment without encryption will look like this:
Select the number of cycles for this subscription. Infinite means the subscription will not stop until it is canceled. If it is a 6 months subscription, select 6 from the drop down menu.
Offer a trial period. If the billing amount is zero, it will be free for the trial period. The trial period has only one cycle. So if you offer first 3 months free, you should set the trial period to 3 months and the billing amount to zero.
Offer a 2nd trial period. The 2nd trial period has one cycle only. For example, you offer 1 month free and then another month 20 before charging the regular monthly payment of 50. You will set the trial period to 1 month and the billing amount zero. Then set the 2nd trial period to 1 month and the billing amount to 20. On the third month, the 50 dollars will be charged.