i found the sling soooo hard! everytime i tried to put him in it he woke up! i think you might need two people, to hole the two straps apart. i than lied them on his belly on the strap and quickly fastened the two velcroe pieces around him. does that make any sense?? than i would tick a blanket it in around his arms and sides and let his legs hang loose.
ohh ya and i would lay a thin blanket over the sling part where they put their heads to make it more comfortable and just incase they spit up you dont have to wash the whole thing!
i hope it works for you!!!