What do you need to know? They are really simple to use but may need a little practice. Mei Tais are basically a fabric rectangle with a strap coming out from each corner, 2 are long and 2 are short. I preferred baby tummy because 1.) it was easier to learn and 2.) I use a backpack for belonging and was completly ands free. So that said, to put on tie the short straps around your waist (like and apron) snuggly in a KNOT to prevent straps from coming undone. Bows can easily come untied which may be a safety issue. Then pick up baby while supporting baby bring the rectangular piece between child's legs. Then you need to bring the long straps up and behind your back. I liked the straps criss crossed so to do that you reach behind you with one hand while holding baby the other to grab the strap on the opposite side. Once you have the strap you bring it around your torso to the front making sure the strap isn't twisted and is flat and snug against your body. Next, while firmly holding the strap you going switch arms to grab the second strap and bring it around to the front. Again making sure the strap is snug, flat, and not twisted against your body. Once you have a good grip and each strap is snug and secure you may tie them in a knot behind childs back or underneath babies tushie. After that you may need to make a few adjustments to get baby seated just right or thighten straps. The goal is to get baby positioned in your center of gravity. If the mei tai isn't tied snuggly enough baby will hang too loose and through off your center of gravity which will be uncomfortable for you. That is great that you have a friend you can borrow from. Do try to get together with your friend for practice and a trial run. The moms on the babywearer are very helpful with any questions you may have. I used my sling until my nephew was almost 4. One of these days I want to try my nephew in my nearly 5yo nephew in my mei tai just to see. But 35lbs is the recommended max. weight.