apache is the most popular web server around, there is a lot of
information on it, just google specific questions.
index.html should show automatically before anything else in the
lets say your domain is http://www.yqcomputer.com/
as long as the home page for that site is under the root of your web
server ie; htdocs
then when you goto http://www.yqcomputer.com/
that index.html page should
htm and html are one and the same, html is the preferred tradition, you
can change the default from index.html to
or whatever you want it to be.
just find the below line in the httpd.conf file
DirectoryIndex index.html index.html.var index.htm index.php
and append onto that line whatever you would like to be used as the
default home page for each directory, you can replace any of the above