There could be a few reasons:
1. The content has not downloaded onto your iPad yet. In this case the class will appear but will be greyed out with a rotating progress wheel in the centre. Once the content downloads, the rotating progress wheel will disappear. You can check the status of downloads within the App by going to 'Settings', 'Manage downloads', any that appear greyed out are not downloaded.
2. Your iPad is not connected to the internet.
3. Your iPad is not synced with the scheduler. To test if your iPad is sync'd, make a change to the studio name, does this mirror on the iPad? If not, follow the below steps:
a. On the APP unlock the padlock
b. Go to Settings
c. Go to Device Settings
d. Go to Change Admin Password
Does the app now come back online? To test please change the studio name, wait a few minutes and see if the studio name changes on the ipad, if it does, all is Ok and the ipad is now syncing again.