404 error problem

I'm confused. I followed the instructions exactly: downloaded the html and css files with curl, then renamed the neat.html to index.html. However, when I opened up index.html in my code editor (Brackets) and launched a local server to open it, I just got 404 error message. To make things more confusing, I see that the 404 message is contained in the index.html file itself - so neat.html is a 404 file? I don't understand why I'm getting a 404 message - should I not be running the file in a server? Do I need to delete the 404 part and add in new content of my own? Sorry but the instructions are very unclear.