You need to finish the floors before you can put up the wallpaper.
This wood has almost no grain visible. It seems to be birch because it is very light, almost white, and has no grain. It is also not as porous because it doesn't see to soak up stain very well. It's almost like trying to stain plastic. This can affect the way your stain looks. I used a brush to try and get some kind of grain effect but you can use a foam brush.
I also stained the staircase so it will be ready.
The dark edges of the wood pieces, compliment the stain.