There is something that confuses me a lot. I do have the Chariot Cougar 1 and this infant slling, as shown in the video. Both products are second hand. at Min 00:22 in the video instruction the infant sling is empty, at 00:34 there is a black and red buckle attached to it. The man clearly inserted the left shoulder strap from below the sling, not the red and bleck buckle. So where does it come from? Is it attached to the sling? Should I buy a sling with this buckle? Our Chariot 1 has a different black buckle built in the standard seat, no red button. So how would I use the infant sling without this buckle shown in the video?