I had my 17 year old put them together for me, I bought a smaller and a larger one.  We ziptied the bottom sections to the rails so my small dog wouldn't get out under the chain link and I put a couple of tarps on the top.  It is where he stays when I'm at work during the day, very happy with these, I'm contemplating buying a couple more for our other dogs.

Pros: Easy to assemble