ClassCast is the easiest way to send links to other iOS devices. Use the teacher client to send links and the student client to receive them via push notifications.
When you build each app you should see warnings about missing API urls. You will need an api base url to a ClassCast server.
To enable push notifications you will need to create an App Id, enable push notifications, and create the provisioning profile with the App Id.
To enable the ability to purchase subscriptions you will need to create an App in iTunes Connect, enable In App Purchases, and create the products (1 month and 1 year are available). Enter the product ids in the configuration files. Purchases are verified and added to accounts through a ClassCast server.