DDR, you may want to read this to get you started http://www.woodfloordoctor.com/
The process sounds simple enough 'sand floor' but takes a certain amount of practice to learn how to use large sanders without creating large divots and ridges.
See if you can locate a local refinisher who will let you watch him work, supply your own ear and eye protection. Note the size of the guys arms, the equipment is heavy and a real workout to use. Buy lots of Bengay.
Check out the site and come back with more questions.