Hey, how do I download it?
This is a warmer, and there is nothing to download. It's just an idea for your lesson, not a worksheet.
Have a little Present contest competition where your students will compete to write or say as many things as possible in this tense. Each sentence must describe something that is currently happening in the classroom. You can set a time limit of, say, 2 minutes, and see how many sentences each of them can come up with. A variation of this activity can be describing an image (make sure you choose one with a lot of action happening), or describing something they can see out of the window.