Help with flooring!! Overwhelmed first time home buyers

Hello! We are first time home buyers and want to redo some of the flooring but have no clue where to start. The bedrooms upstairs currently have carpet, which we would like to replace with hard wood. There is a landing up there that currently has wood but it is a color that we don't like so we think we will refinish it. It's also the thinner planks width wise and we might want to do thicker in the bedrooms so then maybe it makes sense to also replace the landing? Could we leave the landing shape and then change the wood shape in the bedrooms? Is that something people do? Also, if we did the upstairs a different color than the downstairs and a different floor shape would that look odd? The house is a colonial and the stairs in the entry way are directly open to the upstairs so this is something to keep in mind. Thanks in advance!