This is where you dye the pieces, then let them dry. You can dye them as soon as they have been cut out.
¡¡¡WARNING!!!
Try not to get the dye on your fingers. Leather dye is created to color leather. Leather is skin. Your fingers are covered with skin. The dye sticks to fingers and fingernails.
Protect your work surface with newspaper/newsprint or the plastic like the liner of a cereal box (see tracing film) to keep it from becoming gaudily color splotched. If it's not your work surface, ask the owner for approval, and maybe a little help.
Protective gloves are good. A wool dauber for an applicator is good. Use a different one for each color. You may save them to use again (for the same colors.)
Depending on the dye, and on the leather, the dye may go on more evenly when the leather is a little damp. Try it on scraps first, and see what works best for you.
YOU DID NOT THROW AWAY ALL THOSE SCRAPS! You need a few to test the dye on.
I like to let the dye dry overnight, because I find that, once dry, it bleeds less onto other things while I am forming the pieces.