You will need sign into the Miami Gateway which will take you to your dashboard. In the Miami Services - Single Sign On section you will find the icon for ShowingTime referenced in the below screenshot. Click the icon to access your profile settings.
Once you are in your profile click the Edit Profile button referenced in the below below screenshot.
Once you are in your profile scroll all the way down until you see section Mobile App Access. Enter your e-mail address and click Send Authentication Link.
Download the ShowingTime app and access the authentication Link provided in your e-mail. Once you click the link you will be automatically signed in your ShowingTime application.