Hi,
I am wondering. I took the carpet off of the stairs and the wood is in really good shape. I was curious why I couldn't just sand and stain the wood already there without adding any hardwood fixings to them?

You certainly can, if you have the skills and proper tools. In many ways, it's easier to refinish good stairs than install new ones.

I am confused about the right tools. A sander, proper stain and a sealant should all you would need. We are going to tile the riser.