I can't choose my own disk

I’m trying to select my own disk but it doesn’t click

That drive is showing as your current system’s drive and Etcher doesn’t let you flash or write to that drive because the drive is currently in use and would cause corruption to your operating system. If you want to flash to that drive you will need to boot into a different operating system and mount the drive to be flashed. Just make sure that this is what you want because this will overwrite the operating system that is currently on the drive.