3층으로 가세요!
What does “3층으로” really mean? Does “1층으로” refer to the first floor (as in British English) or the ground floor (what the Americans call the first floor)? Suppose I am currently on the second floor how many floors do I have to go up when someone tells me “3층으로 가세요” (one or three)?
Would it make any difference if he or she said "3층으로 올라가세요."?

Question

Answer

The ground floor is the first floor in Korea where you enter the buliding.

Answer

In general, Korean mention from 1st floor as ground floor in the building. "층"means floor, "으로" means going forward and destination. If you're in 2nd floor, then you have to upstair 1 floor more.

Answer

'3층으로 가세요' means 'go to the third floor''. In this sentence, '으로' corresponds to 'to'. Said with '올라', It means 'go up to the third floor'