Quick home electric question

Hey guys

We are supposed to have some winter storms coming in, so I decided to get a generator (me and just about everyone else in town)

I got the whole thing hardwired into what I though was my main panel BUT when I pulled the main breaker (labeled 200 amps) nothing happened
I checked a secondary breaker box and found a breaker labeled "garage panel"

When I flipped the main (100 amp) breaker on the second box the entire house went dark

So, apart from not being able to lock out the 30 amp breaker to the generator, as long as the actual main is of, I can power my house through the genny, right?


On a side note, I guess the 200 amp breaker goes to the box outside, in the bottom picture, anyone know what it is for?

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