how to install this strap on a double end bag

[Toda]

://store.titleboxing.com/debs.html

wow put http in front of : cuz it wont let me link url


how i install this

i'm quite confused...

help, i got this because i'm moving my bag to the garage and the cieling is high so i need a longer/adjustable upper rope

help please quick i need to punch ****