I used the Maya wrap and the Nojo baby sling which looks like the Sling EZee.
How old is your son? When my boys were infants I would lay them down in the sling, or have them upright on my chest. At about 3-4 months of age I would make a pouch in front and would sit the baby in the pouch facing out. I would have one hand on them, but they loved looking out. After 6 or 8 months, I would wear them on my hip. I would put the sling on, would pull the sling over a child as I eased them onto my hip, would tuck the sling under their bottom and would pull tight. I can still wear my 3 year old like that. He's 37 pounds!
One trick - fan the sling out over the opposite sholder from your baby in the hip hold. It helps to balance out the weight and prevents your neck from hurting.
Try this site for photos. Good luck!
Try this website for photos. It's a different sling then yours, but the concepts are the same.
http://www.bundlesofluv.ca/instructions.html