>>1525671it's not an exact science, go to five different bike fitters and they'll give you five different fits
choosing a frame size isn't too hard, go mainly by the manufacturer's height recommendation and the standover height, with about 1" of gooch clearance for a horizontal top tube bike and about 2" for a sloped top tube bike, and cross reference the stack and reach with similar bikes from other brands, you might want to round down if you're between sizes
the saddle height you can figure out by getting within the ballpark using several different methods that agree within less than a centimeter or so and then adjusting it based on feel
the saddle tilt should be level or tilted down by a few degrees at most (inb4 contrarians, see
https://www.youtube.com/watch?v=lmdCc_8e4vI)
the saddle fore and aft should be about as forward as you're comfortable with for better power generation, or with a little bit of setback if you're more endurance and comfort orientated
as for the stem, figure out what goals you have with aero vs endurance and keep in mind your body can adapt within reason and your arms can be moved in an arc so you can have a longer stem in a higher position or a shorter stem in a lower position, you really can rely on your intuition and adjust your position with spacers or by flipping the stem, in the worst case you'll just have to buy another $20 stem, see also:
http://yojimg.net/bike/web_tools/stem.php 
