Put biscuits in a zip lock plastic bag (get rid of any air), then put this bag inside a second bag (also with no air) and crush biscuits with a wooden rolling pin until they form biscuit crumbs
Mix biscuit crumbs in a bowl with cocoa, coconut (save one lot of the coconut to roll balls in at the end) and condensed milk and stir until mixed
Roll mixture into small balls (I use 1 tbsp of mixture per ball)
Then roll these balls in the remaining coconut to coat them
Place in the fridge to set
This recipe can make quite a variable number of balls depending on how big you make them. I use about 1 tbsp of mixture per ball and it makes ~40 balls which are 80 calories each.