How to make chocolate truffles with milk at home

*I got about 32 chocolate truffles with this recipe.

[Ingredients]
150 g dark chocolate + 150 g milk Chocolate
*Compound chocolate doesn't work.Be sure to use couverture chocolate with cocoa butter.*
(* You can use 300 g of one type of chocolate you like.)

75 ml full fat milk (* The amount of milk has been modified.)

40 g(3 Tbsp) unsalted butter