Simplest way to start after Manual Hass install on RasPi

I followed the installation instructions at

Now, what is the simplest way to start it, maybe after a reboot?

It should autostart as a service

The instructions to set up autostart are here

Maybe the instructions have changed. When you install via, you need to activate Python and then run hass. It does not set up autostart. The link you provided (Autostart using systemd) assumes hass has been installed. When I enter “whereis hass” it does not list anything (only “hass:”). Some step is missing to enable/install hass. Can you help? Thanks