Suggestion… read. There is no comprehensive guide as everyone’s experience is different.
Everyone has his/her own reason for doing this and the route they take to do it…
You first have to decide what you want, what you want it to do…
Start here:
https://github.com/MichMich/MagicMirror
That’s the software side…
as for hardware this again is user preference…
You can voice control
gesture control,
touch control,
etc…
Hardware wise this is a project for Raspberry Pi… yes you can use other ways to build it… search the forums some have used Apples, I’m using 2 RPi’s and about to use a mini itx to build a bigger ‘mirror’…
So this isn’t really someone can sit down and write sentence by sentence how to. It’s a ‘project’ that the user is supposed to actively take part in. Which means reading this forum, the MM website and you can find other’s experiences and ask here if you have specific questions regarding how a particular module works and help with setting them up.