Hass.io no longer exists, the name was changed some time ago.
ADR-0014 refers to a Linux based install of Home Assistant Supervised and the requirements around running a supported installation, not a Windows based Docker install like you are trying to run. You can not add the Supervisor to an install, you need to use one of the supported install methods that uses the Supervisor. See HERE for an excellent explanation of each version of HA.
If you are as new to computers are you state, you may be better off getting yourself a Raspberry Pi 4 and installing the Home Assistant OS image instead. It’s a great jumping off point and uses the Supervisor to update the system as well as HA, and has the add-ons store.