@laursa.eth
Basic traveling in São Paulo:
There's two airports and they're separated by, at least, 1h30 of traffic (if you're lucky). B is the international Guarulhos Airport, A is Congonhas airport.
Congonhas is about 20 min of nice places in São Paulo, the airport is small and flights are domestic until 2028. This does not mean you won't get there coming from foreign countries, but the flight will stop somewhere else first so you can change the aircraft.
Guarulhos is the big one everyone gets lost. 3 terminals, 2 connected internally and one only reachable by bus, can be reached by train from the Barra Funda station (it's actually fast, cheap and safe, costs $0.9) but a drug traffic route so be careful with bags.
Sometimes when you catch a domestic flight here, there will be a sign of "airport change". Avoid these at all costs!! The risk of getting late and losing the flight is high, unless there's 4 or more hours between them