Under Geometry, you have to create a Coordinate System and Construction Surface to cut through the elements. 

Under Analysis Settings, in the Output Controls section, you have to turn on Nodal Forces.

Insert a Probe for the Force Reaction scoped to the construction surface and coordinate system to measure the shear forces created by the elements on one side of the plane. Insert a Probe for Moment Reaction for bending moment.  Repeat with as many planes and probes as you want along the length of the girder.

When you use a Beam element and insert a Bending Moment result or a Shear Force result, you get a graph along the length of the beam.