The geometry property of the BRepVertex object returns a Point3D object.
It's unclear to me what you're trying to do. The Fusion API help has an overview discussing the structure of a model that may help. If you still have any questions feel free to ask them here.
http://help.autodesk.com/view/fusion360/ENU/?guid=GUID-1C3FFADB-52C4-49BB-8981-4A448FFE4442
A vertex is a physical object that represents the connection of two or more edges. It has a position in space which you can get by using the geometry property of the BRepVertex object. It also supports other properties that lets you access the edges that it connects.