I use a great free app called Amphetamine for keeping my Mac "awake" while doing presentations, etc. This app is approved by ITD and it is super easy to use on the fly (without having to dig deep into your Settings menus).
- Once installed, this lightweight app can be quickly turned on or off using an easy access icon that lives along your upper screen toolbar.
- When you need to do a presentation and you don't want your computer to "go to sleep" or the screen to go blank, just click on the icon and select from the drop down menu exactly how long you need the screen to "stay awake".
- You don't have to turn off the app when done, it will simply just "wear off" and your computer will go back to its usual screen saver schedule.
For more info or to download the free app, go here: here:
https://apps.apple.com/us/app/amphetamine/id937984704?mt=12
Here is a quick 1-minute video on how Amphetamine works for keeping your Mac awake.
https://www.youtube.com/watch?v=AmLF2HChiOA