I'm trying to put Ubuntu 18.04 onto a Raspberry Pi 4. As far as I can tell using the preinstalled server image is the best bet, but I cannot find any resources explaining how to "unpack a preinstalled version of Ubuntu-Server onto a target device." What does this mean, and how can I do it?
Does this just mean that instead of flashing the image to the SD card with a tool like BalenaEtcher, I'm just supposed to copy-paste the download's contents onto the card?