Insert On Screen Timer. Free Timer loves Snap View. Here is an example from the students screen.
Set a silent timer clock or choose a sound. When the timer hits zero student screens automatically lock so they can no longer respond. The timer begins counting down.
At the bottom of the screen.
PowerApps timer control When you will add the Timer control in the Powerapps screen then it will appear as below. Click on the Get Add-ins under the dropdown menu under Insert. Select the duration of your timer If you click or tap on the field under Timer name you can enter a name for your timer to replace the default name Timer 1. Add a clock widget Touch and hold any empty section of a Home screen.