Ha! Then you have come to just the right spot at just the right time! If you can make a box call for turkey hunting, you can make a bow. And the arrows. And any of the hundred other things that we fool with around here! You got this, mac!
To start with, tillering is another word for frustrating yourself by chasing away the flat spots in the curve of the limbs as they are being bent. Once you have your stave (as soon as the log has been split it becomes a stave and stays a stave until such time as it can throw an arrow...then it is a bow) split/sawn/chopped/hacked down to the basic dimensions of the bow you want, you begin to "tiller" the limbs. You push and pull on the limbs, looking at how it curves and bends. If there is a spot that is bending too much, you leave it alone! Any part that doesn't bend gets scraped on until such time as its bend matches the rest of the limb and both limbs have similar "tiller" or curve.
Reflex is the limb bending outward and away from you (as you hold it in your hand) and deflex is the opposite, where it bends inward and toward you. The inside of the curved limb is the belly and the outside is the back. Think of it as your torso bending, got it?