On a large cookie sheet you will want to spread out the wax paper, wax side up. This will be your work station. You can skip the cookie sheet but I advise against this. The cookie sheet serves multiple purposes. It helps keep the mess contained and if you decide to set your bark outside to cool or pop it in the freezer the cookie sheets makes that possible.Chop or break up the oreo cookies and spread them around the cookie sheet. I alternated cutting my Oreo cookies in halves and quarters.Spread the pretzels out. If you are using pretzel sticks you can scatter them through the pan. If you are using pretzels try to break them up so there are pieces throughout the sheet.Spread the mint M&Ms, Andes peppermint baking chips and holiday sprinkles throughout the pan.Melt the white chocolate either using a double boiler method or in 30-second intervals in the microwave. When the chocolate is melted, smooth pour it over the cookie sheet. Be sure to pour the melted chocolate over all the cookies, M&Ms, pretzels, sprinkles and Andes chips.Place the cookie tray in the fridge or if it's cool outside you can place it outside to cool.Once the chocolate has hardened, break up the bark into chunks and store in an airtight container.