Add 2 tablespoons of rum to the biscuits and walnuts.
Combine steps 1 and 2 and mix well. Stir until you achieve a good compact mass. Let the mixture rest for about 50 minutes (the mixture needs to cool).
Take a piece of the cooled mixture and shape it into a ball. Finally, roll the ball in your choice of coating. You can choose coconut or cocoa for the coating.
Repeat the process until you have used up all the mixture.