Tie the mei tai on. Tie it higher up on your body for a smaller baby.
You can fold down the waist band of the mei tai to make the body shorter with a small baby. Fold down before you tie it on.
Pick up your baby and place them in the carrier. Make sure the fabric extends from knee to knee, and baby's bum is lower than their knees. You can't see the bum lower than knees here because I used a doll.
Cross the shoulder straps behind your back and bring them around over baby. Cross the straps over baby's bum, and tie in back. Make sure the cross is high so baby can't fall out the side.
^^Over baby's bum..
˅˅Under baby's bum
-it's hard to show with a doll, but the knot is really under the bum, and it cannot slide up.
Edited to add:
Rachel (a babywearing educator and awesome person!) made this video to showcase these instructions: