Use the mesh tool. If you have a clean DWG then you can use the magic wand to create the mesh from the boundary and then apply the contours. The top of the mesh will still be flat so the contours must then be raised to their correct elevations. This is best done in plan (the leftmost item on the pet palette) since there is an "apply to all" function that lets you raise each contour in it's entirety (you can only adjust individual nodes in 3D
).
If the DWG isn't clean it may be easier to enter the metes and bounds for accurate property lines and trace the contours with the spline tool.
There are some subtleties to this, but it is easy enough that you should give it a try and then post any further questions.