As I was beginning to describe in step 7, we used 2 Galvanized Mesh Gate which were 4 ft. long. We also had an extra gate which was much longer, so that we can bring a small tractor in. When you are putting your fencing in, just measure the distance of the fence between two of your posts, and then put up some hinges in the post.
Be sure to scrape away some of the grass that may hinder the gate from smoothly opening and closing. Try to build some sort of stopper for the gate as well. Rocks are perfect candidates.