This function will return the User ID pointer whose trial license is currently being used, or it will return pointer_null if the user is not currently active or if the game is not currently in trial mode.
if gamepad_button_check_pressed(0, gp_start)
var _uid = uwp_license_trial_user();
The above code checks to see if a button is pressed and then checks the app to see if it is running with a trial licence. If it is, then it gets the User ID for licence and opens the help file for that user.