How to deal with wall seepage? The bedroom infiltrated through the outer wall. What is the repair plan from the inside?

The first step is to find out the current leakage point of the wall and the cracks in the external wall, and sweep away the plastering layer of the external wall at the junction of gas and structural beam, the plastering layer of the cracked wall and the large-area cracks in the external wall along the whole crack. Then find out that the money should be cut with a hand-held cutting machine to prevent the plaster layer from coming out prematurely because of vibration. This is the way to deal with water seepage in the wall.