The dimensions are based on inside of pergola so the small arms that stick out add at least 6” more. If you are working with a very tight space make SURE you take this additional measurement into account. I had to cut a few pieces to allow for a custom fit around my chimney
The quality and look of pergola is great
I use bungee cords to secure both sides when expecting heavy winds
You can secure each post to a wooden deck with screws
It also comes with pins to secure to lawn
Overall we are happy with it
It definitely helps to have 2 people put it together 
Follow instructions EXACTLY 
Otherwise you may be taking pieces apart 
They are not great instructions 
You basically look at a drawing and match up parts