You can find this section in HostBill Admin → Settings → Products & Services → Your order page → Your product → Connect with App
Once you add your new product, you may need to connect it with the relevant module.
Activate the module first and connect it with HostBill.
Then, in the Connect with App section select the module you want to connect to this product and App server created in previous steps (available in the drop-down menu). Depending on the module, you will be presented with various configuration options. To learn more about specific modules visit Configure Provisioning Modules articles.