nealtw
Contractor retired
The OP had stated that the water was directed down at the concrete landing and that the leak was immediate. That seems pretty clear that the siding isn't involved.
It is clear now that the wood wasn't protected from the concrete with steel or it has rusted thru. and there should hae been drains above the step for possible water around the door.. I suspect the steps hae moved slightly taking away the slope that should have been there and trapping the water against the house,
With the wood rotted away the water should be falling into the pore strip area and finding it's way out. Hopefully the hole on each side will help that and we can look at the fix.