Install the 'Citrix Workspace App' once on your mobile device.
For an iPad/iPhone you can find it for free in the App Store.
For Android smartphones you can find this for free in the Google Play Store
For Windows Phone you can find this for free in the Windows Phone Store.
You do not need to change any settings in this application.
You can now surf with an internet browser on your mobile device to Athena.
There you have to log in with your UGent login
Now when you start an application in Athena you will download a *.ica file
If you open this *.ica file, it will be automatically be opened with the 'Citrix Workspace App'
Your chosen Athena application will then start