1. Keep the walls clean and dry.
2. Put the tape on the crack and press it tight.
3. Make sure the gap has been covered with tape, then cut off with a knife and di tape, and then brush on the mortar.
4. Let it air-dry and then gently polish it.
5. Fill enough paint to make the surface smooth.
6. Remove the leaking tape. Then, note that all the cracks have been properly repaired, with fine composite materials will be modified around the seam, so that its smooth as new.