Installing WordPress on Localhost with MAMP

I’m working to Install WordPress 4.1.1 locally, on my Mac (OS 10.10.2), using MAMP.

I’ve installed a couple of sites locally before, using this tutorial, but for this latest attempt I keep getting a message that says url Not Found.

I’ve double-checked the tutorial, and I don’t think that I’ve skipped any of the steps. I’ve also contacted the author of the tutorial, but haven’t heard back from him.

Can someone provide me with a good method for troubleshooting this kind of issue?