Then open a picture to be watermarked, select Edit-Fill, click the drop-down button on the right side of the custom pattern, select the set watermark pattern, and then click OK in the upper right corner to watermark the whole picture;
Or switch to the watermark file, select Edit-Define Brush Preset, click OK after naming to save the custom watermark brush, and then add the watermark to the PS brush. Select the brush tool, click the drop-down button to the right of the brush tool in the property bar above, select the custom brush just saved, set the brush size, and click anywhere in the picture to add a watermark.