Masuk - enter
Saya masuk restoran moussaka makan - I enter the restaurant to eat moussaka
Saya masuk = I enter.
Saya keluar = I go out.(leaving).
Also means i Have Entered? Past tense?
Saya sudah masuk - it's the past tense. With "I have" it gets more complicated, because Indonesian is simple and you've got to explain the time.