IF YOU DO NOT HAVE TRANSPARENT MATERIAL AND HOT GLUE TURN BACK NOW BECAUSE THOSE ARE REQUIRED.
Step one: Assemble the core.
Note: Red tabs on the back of the slime's eyes work like the tabs on the top of horse legs.
Note#2: The sides of the slime's mouth is intentionally smaller. In Minecraft, it may be hard to notice but it is. (THANKS GOOTUBE! :D)
Step 2: Fold the connecter piece.
Note#3: Remember, print the Outer Slime & Core piece on Transparent paper (or whatever translucent material you use).
Note#4: Fold the connecter piece in any direction, but the A needs to be facing up.
Step 3: Glue the bottom of the connector to anywhere on the inside of the outer slime.
Step 4: Assemble the rest of the outer slime, then you are done!
UPDATE 2-1-2014 7:35
Fixed the core.
1. Click on the papercraft design image.
2. Make sure it has not been resized by your browser (you might need to click the image again).
3. Print using your browser's Print function.