How to change the face of a surfacegui using a script?

Hey guys, I have the following code.

local surfacegui = Instance.new("SurfaceGui")
	surfacegui.Face = Top

Essentially i'm trying to add a surfacegui to a part and change it so that the surface gui appears on the top of the part. I tried searching online and on the wiki but couldn't figure out how to do this correctly using a script. If someone could help me it would be appreciated!