You can translate these sentences over directly by using the different pronouns in Korean:
I eat --> 나는 먹어요.
You eat --> 너는 먹어요.
He eats --> 그는 먹어요.
We eat --> 우리는 먹어요.
However, in most cases you can determine who is doing the eating by the context. Because of this, pronouns are often left out in Korean.
A: I'm hungry... --> 배 고픈데..
B: Did (you) eat? --> 밥 먹었어?
Here "you" is left out.
A: Want to eat together? --> 같이 먹을래?
B: (I) already ate. --> 벌써 먹었는데
Here "I" is left out. (The `을래='wanna', and `는데='...' , they don't affect the meaning of I/You)