1. The side porch was pulling away from the house. I don't have a good shot of the windows, but looking at them, it was very clear that the outside of the porch was several inches lower than the side next to the house. In addition, the floor sagged dramatically when you walked across it.
2. The first step was to remove the siding, the lower half of the walls and the floor.
3. Once the floor was removed, it became very obvious why so much water has been leaking into the front corner of the basement. The ground level slanted toward the house and especially into the corner to the right of the chimney.