Go back and do step 4 properly if you want the collapse for the legs to work. You are not supposed to be squashing using the centre crease.
So long as you make all of the creases shown in step 11, the legs should collapse nicely. Step 12 isn't very well drawn - the second edge should be parallel with the top edge, not at a slope.
Regards,
Fishy
I once set up an origami PLC. But the business folded.