Glubux's Powerwall (2016)

I wonder if there is a more practical tutorial to route a power generator into the house with sort of a power switch. I don't know the exact phrase but basically I can route a few things like the fridge or the lights to this switch so they switch to the generator when there is an outage.

I know it can be done because I asked an electrician. But I dropped the idea when he said it could cost a lot (if done by a professional).

This is not difficult - you need to dedicate a few circuits (cables) and have them end on the generator (or UPS for some). It requires planning but the cost is not especially high (more cables must be used)

Thanks. I think I got the name of the device, it's called ATS (Automatic Transfer Switch). Is this the things I should install?