Translation:I have set the table.
In Korea a lot of things are implied. And so, if you had talked about someone else before (in the right context) and then said this, you could have easily implied that that other person set the table, but now you are saying it without implying that someone else set the table and therefore the only logical conclusion is that you set the table yourself. (For example, "Nina helped me while i cooked, she set the table". In this context it would have been obvious that Nina was the one setting the table, because you were cooking. Therefore you wouldn't have to specify that "'she' set the table" because you had already set up the scenario to point to Nina setting the table and not you, as you where busy doing something else when the table was being set.) I hope this helped someone and made sense. I believe this to be correct, but if i made any mistakes or have in some way misinterpreted this information or been misinformed, then please feel free to correct me so that i too can learn from my mistakes.
This is the present perfect tense in English, while in Korean it is the simple past (at least, that's what I think). I had the same problem with simple present and present continuous. Does Korean distinguish between tenses other than just past/present/future? Or do you just have figure out the nuances in meaning?