The plans make it easy, this fixture makes it effortless.
This fixture is set up to be used with the Pro Plans. Skip the dado step and insert your ripped side rails into the fixture. Clamp it tight then use a dado router bit to cut your top and middle brace locations. Unclamp and flip your board to cut the final end brace location.
The fixture is set up to be used with a trim router from the box.
Having to unclamp and flip is key to side rails that may be cut slightly long, or short. Doing this ensures your ends are equally set the same. A good habit to keep is to always process the boards through in a way that the first side always stay on the same side (top/bottom) on the finished board.
This fixture is adjustable in 2 ways
You are able to set the tool up to be used with a trim router (3.5" base) or a full size router (6" base).
The moveable fences act as a guide that the edge of the router will butt up against and set your dado distance.
While the plans call for three cross braces, some builders prefer to have 4 cross braces to make the handle directly in the center. To achieve this you'll need to relocate the lower fence to the middle position.
You will want to verify the measurements before making your first cut to ensure that the dado is exactly 1" from the end (using my Pro Plans) to make he legs sit right.