If you for some reason want to use Pocket Code and Catrobat's other apps on a large screen, e.g., on your laptop or on a TV screen, or to show them in a lecture hall using a projector, there are several ways:

1. You can use an emulator like Bluestacks on your PC. Bluestacks https://www.bluestacks.com/ works fairly well and is free (but with ads), and I have used it for many years, but it has limits (e.g., no use of the sensors etc of Pocket Code) and uses a lot of resources on the PC. 
    
2. But there is a simpler and much better solution that is useful in many cases: buy a Samsung phone (for other brands, some of them will have similar solutions, but I am a Samsung user so only know it for Samsung). It can be a used, cheap older Samsung phone - e.g., my old Samsung phone from 2013 still works great with it. Connect the phone to the PC via a USB cable (or via Wifi) using https://www.samsung.com/us/sidesync/ on the PC and https://play.google.com/store/apps/details?id=com.sec.android.sidesync30 on the phone --- everything of Pocket Code will work, including all sensors, even GPS, inclination, the camera, etc. This solution is fast, and it needs only few PC resources, thus also working on older laptops and with older phones. You can project the screen from the phone in full screen resolution, e.g., in a classroom, and in the "present" mode on the PC side, the phone's screen can be made full screen or resized to be smaller, with or without other windows visible, and the screen visible on both the phone and the PC at the same time. It also automatically turns for landscape mode on the PC, and then can be projected truly full screen, without black bars left and right. Additionally, both the mouse and keyboard as well as the normal phone multi-touch screen and camera etc can be used at the same time, and if the laptop has a multi-touch capable screen, that will also work for controlling the multi-touch of an app that is displayed from the phone on the PC's screen. If you connect the PC or laptop to a projector via HDMI or a VGA cable, the phone's screen is displayed on the wall, e.g., in a lecture hall or for a presentation. Of course a large external LCD monitor or TV screen is also possible if it can be used as an external screen of the PC or laptop. I am always using it for presentations for many many years now. Sidesync is directly from Samsung, and free. It is the best solution I think, and costs nothing.
    
3. A similar solution to the previous one and that works on _every_ phone is to install the zoom app https://play.google.com/store/apps/details?id=us.zoom.videomeetings on the phone and use the zoom application on the PC https://www.zoom.us/. This works with every phone and PC, including Android, Windows 10, Linux, iPhones, and Macs.
    
4. If you have a newer high-end Samsung device (starting from Galaxy S8), there is another, newer and better solution from Samsung that is even more powerful, called Dex, https://www.samsung.com/us/explore/dex/ which allows you to use the apps of your phone as separate normal, resizable Windows 10 windows. With this you can also use the apps of the phone on a large screen or projector, again using the keyboard and mouse of the PC, but now the Android phone really like a PC, together with the normal Windows 10 applications, seamlessly together. Many newer well known apps even have a special dex mode offering more features, and we are thinking to offer it too, which would allow, e.g., to have two windows for on app, one showing the stage and the other one showing the IDE part, like in Scratch. It is planned for Pocket Code, but will need significant development. I think the phones need at least Android 9 for Dex to work.
    
5. Another powerful solution, but limited to a 65" and rather expensive, is https://www.samsung.com/us/business/products/displays/interactive/wm-series/flip-55-lh55wmhptwc-za/ (like I have in my room at the university). This allows the large screen like a phone, with touch etc. The costs on Amazon etc are much lower than when buying it directly from Samsung, and it also offers whiteboard options, like drawing on the screen and sending copies of the screen as PDF directly from the monitor. No PC is needed in this case, though a PC can also be projected on the screen. It also works best with Samsung phones, though.
    
6. For the iPhone versions of our apps such as Pocket Code for iPhone, you can also directly project your iPhone's screen to a large HDMI capable TV or projector. You'll need a connector cable from your iPhone to the HDMI socket of the TV or projector, which can be bought from Apple. Everything will work, like described for Samsung and SideSync above, and I also have used it many times for demos. However, you need to directly connect the iPhone to the TV or projector. It does not work via a PC AFAIK.
    
7. Many TVs allow to project directly from a phone, via the WiFi of the TV, without any PC in between. I am also using that a lot for demos.
    
8. Apple TV allows to do something similar wirelessly for Catrobat's apps for iPhones.
    

I think similar solutions (like Samsung's sidesync, which only works with Samsung phones) should exist also from the other major companies like Huawei, LG etc, though I haven't tested them. I am mainly a Samsung user.

Hope this helps!