You should now start by laying-out your width profile. Don't worry about the thickness at this point. Just leave it full thickness (i.e. the red line). You're getting too concerned about the technical aspects of trapping, thickness taper, crown etc. Those are not important in your first few bows. Just focus on getting a bow that shoots. Once the bow is roughly shaped in width, you can determine how much wood you have left to spare. If possible, you could trap it a bit, but that is really not necessary. Start with the green width, and the red thickness. If that turns out to be way too stiff when floor tillering, remove some thickness (resulting in the green outline). If it's still too stiff, you could remove wood by trapping the back. Still too stiff? Remove wood until you get the green thickness, but the red width. Just sneak up on your draw weight.
If you have a finished bow (any bow, even modern recurve is fine), you can use that as a training device to get a feel for floor tillering. Push that bow onto the floor, as you would floor tiller a stave. And compare that feeling to your stave.
