what is the function of 에 in this sentence?

[Vitoria]

in '책상 위에 컴퓨터가 있어요', what role does 에 play exactly? I mean, why does it come after the preposition '위' (on)?
thanks for the help <3

[contactus_231994]

Hello,

Thanks for posting. '에' is a place particle and usually means 'at'.
So 책상 위에=at the top of the desk.

Hope this was of help.
Best,
Lyn
Team KoreanClass101.com