Step 1: Prepare a deep baking tray. Step 2: Turn it upside down with the bottom up. Step 3: Use better paper, coat it with oil, let it bask in the sun for 10- 15 minutes or blow hot air with a hair dryer for 20 minutes. Step 4: Put oil paper and oil cloth, adjust the position and fold according to the four bottom edges of the baking tray. Step 5: After folding, cut an edge at each corner. Step 6: put it into the baking tray and fold it to adjust the four corners.