How do I set up PayPal with App+?

Where should the PayPal button be located in the process of booking an appointment? There is nothing located on the "PLEASE CHECK THE APPOINTMENT DETAILS BELOW AND CONFIRM:" area that appears once a day and start time is selected.

I've set up App+ to accept payment through PayPal in the General Settings tab. The client has also created an encrypted button for each service within PayPal. When I click on the button to confirm the appointment I'm taken to the Google Calendar. I can confirm the appointment there but then there is no link or button to pay following that.

Please help as the client is hoping to launch tomorrow, April 29th. I'm sure it's just something I've overlooked.