The following steps take place before the alarm alarms at the set time of 4pm as an example:

1.) Set the alarm for 4pm tomorrow with the clock app.

2.) long pressing of the power key will not power down the unit, instead the ASUI window is displayed showing the time and that the unit is being charge but the charger is not being used.

3.) If I had not long pressed the power key in step 2 but had short pressed the key to bring up the ASUI window, then touch the power off icon in that window the unit will power down.