In Brazil, the military has a special system of ranks to show who is in charge and who has more experience. Just like how your teacher might be a "Miss" or "Mr." and your parents might have jobs with titles like "manager" or "director," everyone in the military has a special name for their rank.
The first rank is called "soldier." This is the starting rank, just like how you start out in kindergarten or first grade. Then, as they gain more experience and show leadership skills, soldiers can be promoted to "corporal," "sergeant," and "suboficial." These are like moving up to second, third, and fourth grade.
The next level is officer ranks. These people are in charge of groups of soldiers and have more responsibility. The first officer rank is "second lieutenant," and as they gain more experience and show leadership skills, they can be promoted to "first lieutenant," "captain," "major," "lieutenant colonel," "colonel," and finally "general."
So, just like how you might move up from kindergarten to first grade and finally to fifth grade, people in the Brazilian military earn higher ranks as they gain more experience and show they are responsible and can lead others.