MAMP version 3.3 on OS X 10.10.4: Server not found

I believe that the instructions/help/support for MAMP may need to be made more robust or in depth.

I have followed the instructions, done my own research, and tried a variety of URLs and browsers in trying to get MAMP running on my Mac. I've asked questions and included all the steps I've taken. I've seen the same or similar questions being asked on Treehouse as wells as on other sites. The questions/problems are often answered once, the answer doesn't work, and the question is never addressed again (admittedly, some people never respond to requests for further information, and others say they figured it out, but don't say how).

The instructions in this video (Install PHP on Mac OS X) tell us to download and install MAMP, change the Apache port to 80, and start the servers. The instructor's MAMP application takes his browser to localhost/MAMP/?language=English, which displays as a welcome page saying, "Welcome to MAMP. If you can see this page, MAMP is installed on your Mac and everything is working!"

I get a "Server not found" message. Firefox, Chrome, and Safari are all showing this message or something to the same effect. Firefox, in particular, or maybe just more obviously, is "redirecting" the URL http://localhost (and any permutations thereof - http://localhost:8888, etc.) to www.localhost.com, etc (I've tried a number of different port options & combinations & URLs).

I did get a response on the MAMP Stackoverflow forum with the following:

"First try it in a different browser and also try going to http://127.0.0.1:8888/. If that doesn't work, check your Proxy settings in firefox by doing the following:

Go to Options->Advanced->Network. In the "Connection" section press "Settings" to open the "Connection Settings".
The "No proxy for:" text field should contain the following text: "localhost, 127.0.0.1"

"if it doesn't say that do this:

Select "Manual proxy configuration:"
Type "localhost, 127.0.0.1" in the "No proxy for:" text field"

Having changed the Apache port from 8888 to 80 as instructed, if I direct any of these three browsers to 127.0.0.1 I am taken to a page that simply says, "Index of/".

Obviously, there is some sort of progress taking place, but I really am no closer to knowing if it is actually working. What does this "Index of/" page mean? Has the MAMP WebStart page been scrapped in version 3.3? The MAMP online documentation says that it is still in effect. Why can I not access it? How do I know what's going on? Do I need to edit some configuration file? I've seen a number of mentions about editing a file in private/etc/, but the changes are not the same across all of these mentions, so I'm not going to mess with it unless I know that the changes are particular to my operating system, MAMP version, and situation.

Treehouse might consider expanding support documentation on this tricky process. I unsderstand that there are a lot of variations in what computers, MAMP versions, operating systems, etc. that students are using, but there has to be some base starting points that will solve these problems, or at least let us know about changes to what we should expect to see.