On the top row, flip the piggies under for a little extra flair. You don't HAVE to do this step, it just makes the top look a little more pretty.
Here is the bottom view. I also flipped these piggies, but, like I said, you don't HAVE to.
Now, once you get all 18 piggies done (and flipped) you take the piggies on the right and attatch them to the piggies on the left. If numbers help, take front piggy 4 over to middle piggy 1. Take front piggy 5 over to middle piggy 2. Take front piggy 6 over to middle piggy 3.
Repeat this process on the bottom. Bottom 4 to middle 1. Bottom 5 to middle 2. And bottom 6 to middle 3.
Then, you do the same thing with the other side. Only this time, you weave the strands over and under the piggies that are already attatched. To weave, just go over the first strand, under the second and over the third. Then, with your second strand, go under, over, under. With the third strand, go over, under, over. I think a Topsy-Tail would work wonders to weave with, but since I don't own one, I just use my fingers and my comb. So, front 1 to middle 4. Front 2 to middle 5. And front 3 to middle 6.
Once you are done attatching and weaving the piggies, make your messy buns. Now, I am NOT good at messy buns. If anyone has a sure-fire way to get a good messy bun every time, I would love you for sharing. I just scrunch up the hair into a ball and put a tiny elastic around the base of it, then spread it out until it looks good.