You could, of course, pop out the tabs and flatten the box, but that's no fun! I'll show you another way. One that will better exercise your fingers and look cool when it's done.
First, drink all the juice out of the container. When box is empty, proceed to step 1.
Step 2: Pop out sides and fold
Step 3: Fold base up to be parallel with the rest of the box.
Step 4: Turn box around and fold
Step 5: Fold cross-ways and tuck.
Sure, in the end it's a useless and inefficient skill, but you have to admit it's fun!