Alright, listen up carefully to this one. OS 10.2.0.483 has leaked for the both the BlackBerry Z10 and the BlackBerry Q10 (check your specific device model in the forums) but this one comes with a few extra cautionary measures and install instructions. First step, you need to download the developer version of BlackBerry 10.2 for your respective device from the BlackBerry developer site, install it and set it up to the point where you're past all of the tutorials. This will wipe your device entirely. Second step, you'll need to download the OS only file loader for 10.2.0.483 and install it and once again, complete the set up process. You'll then be on OS 10.2.0.483.
Keep in mind, this is a very beta leak and it will superimpose your BlackBerry PIN on your device display. There is no way to remove this as long as this OS is installed. If you're not fine with that, move on. This isn't something you want to install or use. Also keep in mind, some things are not going to work properly at all times. If you're not fine with that, move on. Don't install this. In short, if you rely on your device and always need it working, you might want to pass on this and of course, you can't blame us if you break your device. You install this at your own risk.