If you can get your hands on some leaf fat from your butcher it is really easy to render fat....put the fat in a food processor to make a paste. Put that into a double boiler...I use my Kitchen Aid metal bowl set over a large pot of simmering water. Let it go most of the day. Put it through a fine strainer into sterilized jars and store in fridge and/or freezer.
i get pork leaf lard from my butcher...they keep it frozen. Beef leaf lard might require a special order.