I think I can give you some KEY events that would be good. First of all, you should note the Discovery of Brazil by Cabral, the plantation-era: centuries of sugar, coffee, valuable things Europeans liked to consume. Talk about how around 70% of all African Slaves ended up in Brazil. Then there are the disputes with other European powers such as The Netherlands, France, the Spanish. Also an important time is when the Portuguese Royal Court fled Portugal and relocated to Brazil. This is known as A transferência da corte portuguesa para o Brasil. Definitely include this as it ties in with the Napoleonic Wars. Lastly, slavery was not officially abolished until 1888. This was the last country in the Americas to do so. In the 20th Century, there are a handful of coup d'etats until the military-dictatorship ends in the 1980s. This is when "modern" Brazilian democracy finally wins.
Brazil has an immensely long and dark history, but these are major periods since the "discovery and founding" of what today is Brazil.