It depends on how your field data is organized, probably you already have a surface for the existing ground so you need to create a surface for the design (field data).
If the field data is organized as station and offset you could use "Draw from coordinates", "Block at station/Offset from polyline" to place a block in the drawing and then triangulate. If field data is in coordinate format you can plot them to the dwg as points and then triangulate. After triangulation you may delete unwanted triangles and then save triangles to file (Edit/View triangles)
Finally you create surface cross sections along the alignment (polyline) and plot them to the drawing. Calculating cut and fill can be done by surface volume or by first create areas in the cross-sections and then calculate volumes manually. (Lines, Cross-section area)
Hope this helps