How do you update the PS4 with the new 4.00 update?

I went to the website and downloaded the file. (It downloaded as a PDF - is this my problem?) Then, I bought a 32GB flash drive (the file needs 297MB, so that's not the problem) and put the correct folders on it (PS4, then, inside that, UPDATE) and put the file in the UPDATE folder. I named it the correct title (PS4UPDATE.PUP). Then, I went to my console and put in the flash drive. It did a system update (which was what it was doing every time I turned it on), finished that, and told me to put in the power cord with a controller. I did, and pressed the PS4 button. Then, it gave me the instructions to put in the flash drive with the update file installed. It did. I pressed the button, and it said that it "couldn't use the file." What's up with that? What am I doing wrong? How can I update my PS4?