Practice over a couch or a bed, in front of a mirror -- it's like riding a bike, you just have to learn the physical movements and then it will seem so easy!
You can definitely try putting the carrier around his body on your front and then scooting the whole thing around. But before you try anything with the carrier, I'd just practice doing piggy back rides with him -- get comfortable getting him on and off your back, whether it's via hip scoot, or super baby (facing him away from you, putting your hands under his armpits, and throwing him up and over your shoulder), or some other way. The more you get comfy getting him on and off your back, the easier it will be to do back carries with any carrier. Just always keep a good grip on some part of his body -- whether his back, bum, or legs -- and realize you're not going to let him fall.