I have used Unsalted Butter and have added little salt to the mixture. In case you are using normal Salted table butter then don't add extra salt.
Since I have used Packaged Whipping Cream with added sugar, I have not added extra Sugar while whipping the Cream. In case you are using normal heavy cream to make the frosting then add 3 Tbsp. of Icing Sugar while Whipping the Cream.