Google "how to install home assistant" which leads to:
>https://www.home-assistant.io/installation/
>If you are unsure of what to choose, follow the Raspberry Pi guide to install Home Assistant Operating System.
This leads to:
>https://www.home-assistant.io/installation/raspberrypi
This has a nice visual guide that requires you to know how to buy a raspberry pi, how to plug in a raspberry p, how to plug in an sd card (twice), and how to navigate to a url.
For someone who doesn't have a Linux background, "just put it on a Raspberry Pi" is kind of like saying "You write a distributed map reduce function in Erlang". Ie: it's easy if they know it, but if they don't then that "just" is doing a lot of work there.
Pre-installed is almost certainly the way to go for such a person.
This is already a job that requires fairly decent electrical knowledge, especially if there are 3-way switches involved.
Turn-key solutions exist for people that don't want to deal with the complexity.