So, there are these beings in the Halo Universe called "Covenant". They are made up of several different species that have come together to form a big group.
Now, these Covenant members have different roles and jobs that they do, like any group or team would.
There are the Grunts, who are like little space goblins that are used as foot soldiers. They aren't very smart, but there are A LOT of them.
Then, there are the Elites, which are the leaders of the Covenant. They are very strong, smart, and skilled in combat.
The Brutes are also part of the Covenant, but they kind of came in later to help out. They are also strong and skilled in combat, but they are a little more hairy and aggressive than the Elites.
Lastly, there are the Prophets, and they are the ones who are really in charge of the Covenant. They are like these big, floating alien guys who are super old and wise (or at least they think they are). They make all the big decisions and tell everyone what to do.
So, these members of the Covenant all work together to achieve their goals, which is usually to find and activate these ancient alien artifacts called "Halo Rings". But, the Covenant is always at war with the humans, so they fight a lot too.
Does that make sense, kiddo?