Be careful with lawn clippings. They have a tendency to form a slimy mass if you add more than a thin layer at a time.
A good fork is all you need to keep the pile aeration if it's cooking at a good pace. There are specialized forks for compost piles too.
You may want to add another bin at the end of your E and move one of the piles there. Use the middle bin for turning. Move a pile from one of the end bins to the middle bin using a fork and shovel, then move it back. By turning a pile occasionally you will aerate it, have a chance to check for balance and moisture and most of all, gain access to the finished compost at the bottom. Be sure to top off the still-cooking pile with some finished compost -- that helps it cook down faster.
It takes a bit of time to figure out the right timing for your bins, but then it becomes second nature. You'll notice that greens (lettuce to kale) and rotting stone fruit break down rapidly, while cabbage family cores and stalks take a while.
Here's one randomly selected composting page, but it explains the basics
http://vegweb.com/composting/how-to.shtml