Past, present, future — and 겠 for what you assume
Korean tense is simpler than English, with one extra tool
Past is 았/었.
가다 → 갔어요, 먹다 → 먹었어요. Vowel ㅏ/ㅗ takes 았, everything else takes 었. 하다 becomes 했어요.
There is no separate perfect tense.
English *I ate* / *I have eaten* / *I had eaten* all land on 먹었어요. Context does the work that English does with auxiliaries.
Future is usually ㄹ 거예요, not 겠.
갈 거예요 is the plain future. 가겠어요 adds intention or a guess — closer to *I will* (determination) or *it must be*.
겠 is how you soften a guess.
맛있겠어요 — *that looks delicious*. You are not stating a fact, you are inferring one. Native speakers use this constantly and learners underuse it.