This isn't a very helpful answer. Why do experienced people do this? Just lack of communication skills or what?
The file you need to find is called (in a Windows OS) httpd.conf. It should be found somewhere under where you (or someone) installed Apache. In my W10 system it is located at D:\apps\Apache24\conf\httpd.conf. If you are delving into Mac or Linux you'll probably be quite a techy person already and be able to find out where your Apache server is installed.
In that .conf file you need to find a crucial line where the DocumentRoot
is set. The location in my httpd.conf file looks like this:
# DocumentRoot "${SRVROOT}/htdocs"
# <Directory "${SRVROOT}/htdocs">
DocumentRoot "X:/htdocs/html"
<Directory "X:/htdocs/html">
... that's because I changed the default location at some point. Hash (#) at the beginning of a line means: comment this line out.
Now my "localhost" home is at X:\htdocs\html\ (where html is a directory). If I put an index.html file there and then go "http://localhost" in my browser it displays the html contents of index.html.
localhost
into your browser? If so, what HTTP server are you using?netstat -bn
on the command line to see which process is listening on which port on your local machine. Maybe that'll allow you to dig deeper :)