This process involves completely stripping down any finish, wax, stain, etc., to the raw state of the wood using heavy duty state-of-the-art sanding equipment.
A matching wood filler is then applied to fill any gaps, cracks, or nail holes.
After meticulous sanding, you may then choose a stain of your choice or keep the natural color of the wood. 
The last step involves applying several coats of durableand protective finish to your desired sheen level (gloss, semi-gloss, satin, matte).