1. After cracks appear in the damaged wall, you can first scrape off the edge of the cracks with a scraper, scrape off the sundries in and around the cracks, and widen the cracks to facilitate filling and embedding.

2. Wet the crack with a brush soaked in water. Prepare the filler and insert it into the gap with a scraper.

3. Push the filler vertically into the crack with a scraper. If the crack is deep, apply another layer after the filler dries.

4. When the filler is not completely dry, flatten it. If it is uneven, it can be smoothed with sandpaper after the filler is dry and hard.