First & foremost, identify which is the front side of the zip. You can see that the zipper's "teeth" is facing down and that's the front side of the zip.
So, this is how a zipper looks like without it's head.
Place the zipper's head like the below.
Then, pull the both side of the zipper towards outside at the same time (saw the chubby finger's of my daughter? So cute... hahahaha)
This is how it will be after pulling both side of the zipper. Neat! (it took me quite some time to ask my daughter's hand to stay still until I can get to snap this photo. Phew~)
Now, you can pull the zipper's head down without problem! Now, it's time to install the the zipper's charm!
Ready your charm as below photo.
Then, push the charm toward's the zipper head like the below photo. There is some kind like a spring inside the zipper's head. (start from this photo below, the fingers shown belongs to Nicky! kekekeke)
Another photo shows you how to push the charm in the zipper's head.
There you go. It's inside already! hehehe... Does it sounds embarrassing? Don't get me wrong ya. hahahaha...
Ahemm... This is how it looks after installed. I like this Snoopy charm. Very cute!
Wondering how to get the charm out from the zipper's head? No worries, just continue to scroll down!
Take something which is sharp enough to poke on the spring area just like the below photo.
It will create an opening and at the same time, you can take the charm out already!
Now, there you go the final photo!