I didn't front carry DS in the Sutemi much -- mostly back carry.
Did you try to put the waist strap on first & one shoulder strap? leave the other strap undone and loose. Put your child in, supporting them, and then attach the second strap? Just practice a lot w/ someon or over the bed
I got this carrier about a week ago....Love it! For the front I found what worked for us (my dd is 13 months) is to put it on around your hips and tighten it. Then you can put one strap on and place your DC in the carrier and tighten that strap. That should hold your DC well enough to get the second strap on. It takes a little practice…especially for the back carrier. Practice in front of the mirror really helped me see where everything was. After a week we can do back, front and side with out the mirror.
This carrier has made going to the grocery store so so much easier!
I did it like the instructions on here: http://sutemigear.com/instructions/ Then, I didn't feel like I was trying to grasp the strap floating somewhere behind my back while holding onto my DS. I just slid him in and out as needed and tightened and loosened the straps as needed.