On top put the second part of the herring, to press her a little on top. Cover with film on all sides. And in refrigerator not less, than on three hours. You can leave so, and if there is a lid, close the lid. This snack can be prepared a day or two before the holiday. For the filling, you can take any products to taste. Cut everything into cubes, mix with the sauce. Pour one half of the herring and cover the other, it will be easier.