Do something that will make them laugh and enjoy themselves.
I gave a seminar once that ended with a demonstration of the terminal, ssh, and nginx. I had everyone go to the url where I was hosting a hello world. I killed the server over ssh and told them to refresh the page. Nothing there. I swapped the page, turned it back on, and told them to refresh the page again. I Rick Rolled them. They all laughed. It may not have been the most informative talk, I didn’t really ‘teach’ them anything, but I got some good questions afterwards.
Be creative and make it fun and they will come to you.