It's straightforward, though. For each column, only countries with flag contains colour of that column are counted. (Therefore, China will appear only for red and yellow and not for any else.)
first of all, it doesnt say 104k miles it says 1.04m, second, they were asking how to play the quiz of course they misunderstood the quiz it was in the comment
Rank Country Square Miles
1. Russia 6,592,735
2. Canada 3,855,081
3. United States 3,718,691
4. China 3,705,386
5. Brazil 3,286,470
6. Australia 2,967,893
7. India 1,269,338
8. Argentina 1,068,296
9. Kazakhstan 1,049,15
I don´t understand the quiz