Type 'easy' or 'hard' to begin the quiz. Easy is a 10-degree grid, hard is a 5-degree grid. Then, try to name the largest South American cities (min 50K population) in each square IN ORDER. To name a city, you must first click on the grid square to make it have a GREEN border. Then, type in the city answer for that square followed by a '.' (a period).
The squares will start with '0/5' (or maybe fewer cities if less exist in that square). Click on a square and enter the largest city in that square not yet answered (so, the largest city if you have yet to answer a city in that square). You will then have '1/5' and need to click on that square to name the 2nd largest city, and so on until you complete all the cities up to 5 (or less if less exist). If you name an incorrect city in a square it becomes 'locked' and turns red and you can no longer accumulate cities in that square.
You receive 1 point for the largest city in a square, 2 for the 2nd largest, and so on.
At the end of the quiz the largest remaining city you haven't named will be shown in each square.
Quiz Takers 
One of the places accepted as an answer was São Domingos, but São Domingos is not actually a city (since in Brazil only municipalities are considered cities). It is a district that is part of the municipality of Brejo da Madre de Deus.
I went by citypopulation.de classification of a major city – it’s listed among them here:
https://www.citypopulation.de/en/brazil/cities/pernambuco/
obrigada