First of all, use a piece of sulfuric acid paper and a piece of cardboard with writing, put the cardboard on the sulfuric acid paper, fold the outline of the cardboard on the sulfuric acid paper, and use a red pen to draw a stamp pattern. Or directly stamp, in the back along the four sides of the double-sided tape, pay attention to the double-sided tape and margins of the same width, cut off the excess margins, the hard cardboard pasted on the inside of the sulfate paper, trim the excess top and bottom corners of the excess margins, it's done.