Cut the pork fat into small cubes, and add to a pot for stove cooking or the pot of a slow cooker. If you are having a hard time cutting the pork fat and skin, you can try placing it in the freezer for a little while to help stabilize it and make it easier to cut. (Don't freeze for too long, though, or it will get too hard to cut)
Heat the fat over low heat, stirring occasionally.
After a little while, you will start to see a transparent, slightly yellowish liquid forming. That liquid is your rendered lard.
Ladle and strain the liquid lard into a glass storage container.
As the yellow liquid starts to cool, it will start to solidify a bit and will get whiter and whiter.
The leftover solid bits, the cracklings, can be baked in the oven and then used to add flavor to dishes or sprinkled on salads (or just eaten alone as a snack).
Nutritional information is based on obtaining 1 quart of lard from 1 kg of pork fat. This is all dependent upon the type of fat used. It also includes eating the proportional amount of cracklings (1/64th), and isn't just accounting for the lard itself.