Roasting a frozen Creole Pork Leg?

I have a cookbook from Panama and the directions are sometimes missing or can be very broad. I'm a new cook so I need exact directions. I've tried Googling too but can't seem to find other recipes that ask to freeze the pork.

Is there a reason it says 24 hours, like it's only partially frozen in 24? And after the 24 hours, I put it on the oven frozen for 2 1/2 hours? Or do you defrost it? Do you cover it?

Ingredients: 10 pound leg of pork 6 garlic cloves 1/2 teaspoon pepper 1 tsp oregano 1 1/2 spoonfuls of olive oil 1 1/2 spoonfuls of vinegar 5 tsp salt

Preparation: Place all the ingredients except the meat in a bowl and crush well. Wash the meat and dry it well. Make superficial cuts with a sharp knife. Cover the meat with the mixture of ground ingredients and place in the freezer for 24 hours. Preheat the oven to 350 F and roast the meat for 2 1/2 hours until well cooked.

Thank you.