Attach a guide collar to the base of your router. Insert a dovetail router bit into your router, and adjust the depth of cut to be equal the thickness of the board into which the pins of the dovetail joint will be cut.
Clamp a piece of scrap wood into the top clamp of the dovetail jig, so that the front edge of the board is flush with the front of the jig.
Insert the board onto which the pins will be cut into the front clamp of the dovetail jig. Slide the board up until the edge is flush with the top of the scrap board installed in the previous step, and tighten the clamp to hold the board.
Insert the guide template into the top of the dovetail jig, with the square pins facing the front of the jig.
Turn on the router and place the base of the router flat on the template. Ease the router bit through the pins in the jig, using the collar on the router to guide the router through the template. Do not force the router, but allow the router to glide through the wood as you cut the pins of the dovetail joint. After completing all of the pins, lift the router from the template and turn off the router.
Remove the template from the dovetail jig. Loosen the clamps on the front of the dovetail jig, and remove the pin board. Insert another board for the tail board into the front clamp until the edge is flush with the scrap board on top of the jig, and tighten the front clamp.
Change out the dovetail bit in the router for a 1/2-inch straight-cutting bit. Adjust the depth of cut to the same thickness as the board being cut.
Install the template with the angled fingers into the top of the dovetail jig. Turn on the router, and place the base of the router onto the top of the template. Ease the router through the angled fingers, using the collar to guide the router through the template to cut the dovetails into the work piece. Do not force the bit through the wood. After completing the tails, lift the router off the template and turn off the router.
Remove the board with the dovetails from the front of the jig. Insert the pins from the pin board into the dovetails you just cut to test the fit of the dovetail joint.