Increase screen time and disable sleep

 Windows 11 typically times out your screen after 5 minutes if you're on battery and 15 minutes if you're plugged in. This is a useful power-saving feature, but it can get annoying having to wiggle your mouse to wake the screen every time during a lesson.

Right-click a blank area on the taskbar, then click Taskbar settings. 

Select System from the sidebar on the left

Choose Power & battery in the pane on the right.

Set a timer for Screen and Sleep options