Problem:

Solution:

In product configuration use: Components→ Forms→ OnApp Cloud Selector.
 

This special form field enables your customer to select from one of available OnApp installations that you've set-up in Settings→Apps.

To setup this field in your product: 


If you have only one install, but multiple zones (some Federated) that you wish customer to select during order, use OnApp Zone Selector field instead



Note: This field imposes some restrictions on your OnApp setup: