M.W.
To make a Mody-type wrap:
Get 4 -6 yds of material, depending on your size. Material should be strong yet soft with little if any give. Fold in half lengthwise. Hem the two ends. You can use this plain, or put some batting or other thin padding material between roughly the middle third of the two halves and sew down the length of it. Get 2 "D" rings and sew them into one end.
However, I found it easier to just make a square of material the about the width of your torso, make a loop from the middle to the bottom of each side.Make two straps about 5 ft long, which may be padded at shoulders for wearing heavier babies and toddlers. Sew the straps to each side of the top side of the square. Hold the baby against your chest, place the sqare on the baby, bring the straps over your shoulders, cross them in the back, bringing them through the loops and back around your waste, tying off in the front under the baby.
This design uses less fabric (which is a plus in the summer, minus in the winter) and holds baby just as securely so you can use both arms and hands for other things.
Both designs can let you wear the baby on front or back, or one front & another on back, but extra hands mayt be needed to accomplish this usage!
M.