When setting up an instance of H2O to handle a form to process PayPal payments, you must dedicate a single instance of the H2O to that form. In other words, you can’t allow users to enter/edit multiple forms/projects in the H2O instance you want to enable with PayPal.  However, you can get around this limitation by using the new Query String Posting feature in H2O.  More details are available here.

To setup PayPal with H2O, click on Edit H2O and then click on User Interactions. At the bottom of the screen you will see the PayPal settings. Complete the settings as described below:

1. Click Edit H2O from the module menu
2. Click on User Interactions
3. Check Enable PayPal Payments
4. The option to Allow Pending Transactions is used in conjunction with the “Add User to Role After Payment” settings. If you check this option, users will be added to the DNN Role you specify if the transaction is Pending or Completed. Otherwise, the user will only be added to the role if the payment is completed.
5. Enter a name for the purchase in the Item Name field.
6. Enter the amount of the purchase in the Amount field. If you want to allow your users to purchase more than one of the item, add a field to your form and name it Quantity. H2O will automatically calculate the price based on the quantity entered by the user.
7. Enter your PayPal email address in the PayPal ID field.
8. Leave the Portal ID field as is unless you want transactions to appear in a different DotNetNuke Portal.
9. To add users to a DNN Role after payment is complete, check the Enabled option for “Add User To Role after Payment” and then select a role from the list provided.
   Click Update.