How do you make such a console?

Since I was little I have been interested in video games.

Starting with Minecraft, Snake and later "real" games

I've been involved in video games for a long time.

Also for retro games- Although I was not born in the generation where you grew up with them, I tried to catch up a lot.

Back then, I saw a typical scraper console on Amazon,

with "200 games in 1" or something like that. I even bought it.

That was a Famiclone with such a NES-Rom menu.

Now to my question:

How do you bring such a menu to such a console?

I've also built a RetroPi console with Raspberry Pi myself,

but I would be very interested in that with these NES clone menus.

Can get you a SNES. There are old Nintendo games

Thanks, but I actually wanted to know how these bootleg consoles work…