After somewhile. you can start building the real diorama of angry bird stage.  The sling is here.  No angry bird stage are complete without the sling.

This sling is for display purpose only, dont expect it to be functional :D

However, with some modification, when you stuffed some hard material inside (i.e. plastic clay), and give it a skeleton, change the rubber straps.  You can function the sling.

Actual model built by Adhiwardhana Widjajanto

You can find the instruction in the instruction page

Please carefully read the licence agreement before you proceed with the download
Angry Birds Sling Papercraft