Someone has passed on a Wilkinet carrier to me. I have heard that they can be worn on the back as well as the front but the only clue I have as to how to wear it at all is the pic of happy mum& babe in NCT catalogue. (shown wearing on front, no mention of back). So it is just lying sprawled on the sofa, straps akimbo. How do I put it on? This must be impossible to describe but I'd appreciate any attempts!