Solution:

1. First make sure to enable the feature "Rental Transfers":

2. Create a new Rental Order and add all of the required information:

3. When you Confirm the Rental Order a Delivery Order and a Return transfer will be created:

4. If you Validate the Delivery Order, the Pickup button will be automatically triggered and it will become the Return button. If instead, you click on the Pickup button, it will take you to the Delivery Order and you can Validate it:

5. Also, when it's time to return the rented product, when you Validate the inbound transfer the Return button will be triggered automatically. If you click on the Return button instead, it will take you to the inbound transfer and you Validate it: