1. Step 1: Check the water hole of the washbasin and determine the size of the drain pipe, as shown in the figure below, and enter the following steps.

2. Step 2: After the above operations are completed, purchase related accessories according to the size of the hole, as shown in the following figure, and enter the following steps.

3. Step 3: After the above operations are completed, the fittings of the sewer pipe are divided into two parts, as shown below, and then the following steps are carried out.

4. Step 4: After the above operations are completed, the lower part of the sewer pipe is divided into a water-blocking sealing ring and a fixing nut, as shown in the figure below, and then the following steps are carried out.

5. Step 5: After the above operations are completed, put the upper part of the accessory into the hole of the washbasin, as shown in the figure below, and proceed to the next step.

6. Step 6: After completing the above operations, start to install the water-blocking seal, as shown in the figure below, and enter the following steps.

7. Step 7: After completing the above operations, fix the waterproof sealing ring and the fixing nut, as shown in the figure below, and enter the following steps.

8. Step 8: After completing the above operations, put the water pipe below, as shown in the figure below, and enter the following steps.

9. Step 9: After the above operations are completed, install the sealing rubber ring, as shown in the figure below. In this way, the problem is solved.