With the 'Timer' component, you can place a timer (or clock) anywhere on your slide.
Step 1
Click on '+ Component', and then on 'Timer'.
Just like with the other components, you can resize the timer by adjusting the size of the frame.
Step 2
You can adjust the time by clicking on it in the timer. This can be done beforehand or during the lesson.
Step 3
For more advanced options to customise the timer, click on the cogwheel icon in the box, and then click on the pencil icon.