Here is a simple guide on how to make a DTD construction. More detailed instructions linked at the bottom.
Get a friend, spouse, and or family member to help you out. Do not do this process alone.
Wear a painter's coveralls overtop of cheap clothes you wouldn't mind getting a cut up.
Tape up your entire body with high quality tape.
Tape your body up to your neck line/collar bone, to your wrists, and down past your heel.
A tracing of your foot and hand are very helpful as well.
Keep your arts out, body straight, and legs spread in an A-pose while being taped.
Tape as close to your body as possible without it being uncomfortable. Do not leave spaces of air around your crotch or armpits.
Mark the places where you will be cutting your friend out with one long line and X's every few inches.
Try to limit how many exit holes you cut. You should only need to cut from your neck down one side of your body and halfway up the remaining limbs.
Use a spoon for leverage and scissors to cut. You can get trauma shears for the safest way yo cut out of a DTD.
Retape your DTD back together and label it with you and your characters names.
You can refer to Golden Maw’s tutorial, or Skypro’s video tutorial, for a more detailed guide.