You’ve probably also seen those videos online where multiple versions of people are walking around greeting each other, pretending to be different people, confronting their past selves – there’s a whole lot of options here. The process is called cloning yourself, and it’s a lot easier than it looks. First, you’ll want to look for a video app that offers multilayering, or combining different layers of video together (also helpful for your whip pans, although not as necessary there).
Video Star offers multilayering, but many video apps have it, so feel free to look around. Then, using a tripod, create several separate videos of yourself in the same spot, and layer them together. It may take a bit of practice to look right (and avoid running into yourself), but once you get the hang of it, it’s no problem.