What is the most logical next event?

How to finish pine stair treads
Use a power sander and a medium-grade disc to sand the treads.
Attach a medium-grade sanding disc to a power sander, plug it in, and turn it on. Go over the entire surface of each tread to start smoothing out the roughness of the wood.
It's necessary to sand the surface of your treads before doing anything else. This should remove the unsightly orange tint of the pine, buff out scratches, and also allow the pine to better accept the stain.