No worries Luke,
you mix the solid timbermate from the container with water into another container and mix a slurry. Not too thick and not too thin. Wipe it all over the cap. You can even wipe it over the whole body would go well on the mahogany body.
Let it dry overnight and I'd sand the cap from about 180 to 240 or no more than 320 grit. Back and sides you can sand to about 320 grit.
Might pay to make a hanger for the body get some cheap pine as wide as the neck pickup and roughly cut the shape. Use two wedge shaped pieces of wood to keep it in place.
In terms of curing DB recommends about 3 days in summer so might need about 5 days curing in cooler weather.
If you can leave it indoors to cure it should cure faster. The Dingotone has a lovely natural smell to it and doesn't contain any dangerous chemicals.
Attached are some close ups of a set neck (glued) neck hanger and wedges to hold it in place