To make it?
I participated once when I was a Kid, but...
After kiling the pig, you take pork meat and fat, and you mix it and mince it. Then (i believe) you mix it with (sweet usually) red pepper powder and salt, and spice pepper if you wish. Then you let it rest three days, and then press it into the pig guts, previously super-thoroughly washed and then rested in a vinegar solution to disinfect (or you can buy washed guts), or into similar cellulose ones.
Then you smoke it or not, depnding on your likes, and leave them hanging form the ceiling of a ventilated room with the threads you use to tie the ends of the sausage.
There is an inferior quality chorizo that is not made from meat but (I believe) lungs or so, that is called "chorizo sabadeño".
Anyone can add sth.? Because if you plan to do it yourself, I wouldn't like you to miss any details or it could get spoilt.