After catching one, you bite the eyes to dispatch it. After getting it home, you turn it inside out and remove its internals. Sometimes you save the ink bag to use if your serving it raw. In this case, I am drying it, so no need the ink.
You then "villi" the creature by repeatedly dripping it into a five gallon bucket with sea salt. This helps get the slime out, and causes the legs to curl. A lot of foam is created, and this can take a half hour or so.
After, you cut out the beak and eyes, then cut off each leg, and portion the body. I spread it out in direct sunlight with sea salt in my dry box. The amount of sunlight and length of time is determined by how dry you want it.
I dry ours enough to be able to easily separate in your mouth. It has a consistency of beef chunk jerky. It's absolutely delicious, and highly valued. It does not last long before it's all eaten.
There are other ways to prepare an octopus as well, but dried is my favorite. It is one of those snacks that pairs well with a good beer and friends.