The no obligation free trial requires you to sign up to the subscription service with a PayPal account.
You can then cancel your subscription any time you like via your PayPal account.
If you are happy with the product and you wish to continue using the product you do not have to do anything as after 30 days your PayPal account will be charged your subscription amount.
Note: If you do not wish to continue on with the service you must cancel your subscription via your PayPal account within the 30 day free period.