I butchered two hogs awhile back. I saved all the fat. I used a big two burner fish cooking pan. Filled the pan full of the fat and slowly let it melt on low heat. Once the pan had enough melted fat, I turned up the heat to around 325. This fried the cracklings. Once the cracklings were crispy, I removed the pan from the heat, removed the cracklings, and let the grease set up. Once it is set up, it is rendered lard.
Some people use an oven, I use my two burner propane cooker. I used a long thermometer that I have for deep frying to determine temperature.
As I described earlier, I used the lard because I didn't have any bacon on hand.
Hope that helped
Jodie