The last assembly step in building the table saw jointer jig is to attach the miter strip to the base of the jig.
As you're facing the table saw, measure from the left side of your saw blade to the right edge of the left miter slot. Add one-eighth of an inch to this measurement.
Next, turn over the jig and measure that distance from the right-hand side of the jig. Using a straight-edge, mark a parallel line at this distance from the right edge of the jig.
Finally, position the strip (with the wide edge against the base of the jointer jig) on the edge of the line opposite the right-side of the jig, and attach to the jig with some 1-1/4" deck screws. Be sure to pre-drill and countersink the screws to be sure the heads recess and do not protrude past the face of the strip.