If your computer or laptop is connected to a projector you can use your computer while projecting other content on via your projector. The process is simple, but you will want to try it before you intend to do it in front of your class.
Once you have done that, the screen that is projected is different than what is showing on your screen. Move your cursor to the right or left until you see which direction it connected. On your main screen, open what you want to project, then click and hold to drag a different site/screen onto the projector and interact with it independently of whatever is shown on your computer screen.
*To disconnect the second screen, click PC screen only.
Here’s a video of the process:
Last, here’s an article and video to help you do this: