To access the main FOS application on your iPad follow the below instructions.
Open the device app store and search for "Citrix Receiver'.
Install the application onto your device. If you have not done so already you may need to create an account with the device manufacturer.
If the Citrix Receiver setup dialog opens after installation, you may close that and move to the next step.
Open Safari to your FlightApps webpage portal.flightapps.com or login.flightapps.com
Press Open in Receiver
The app will launch from the Citrix Receiver app you just installed.
Log into your FOS app as you would on the desktop