So excited for my first trip to Brazil!

I'm trying to book a multi-city itinerary so that I can fly into GIG, go visit IGU and fly home to SFO from IGU with a long connection in GRU (just so I can go see a bit of Sao Paolo on the way out). I like the idea of this being on one ticket so that a checked bag can be included, and also so that if I'm delayed out of IGU for some reason, then it is up to the airline to rebook me versus booking 2 separate tickets and being out of luck

I don't see any option for Multi-City bookings on the US LATAM site. Is it hidden somewhere else or do I just need to use something like Google Flights?

Also, is there a way to know what booking code the fare I'm selecting books into? I'm trying to determine how many Alaska EQMs I will earn (MVP Gold there).

Thanks so much!