I am assuming here that you have all of this set up on your own computer right there in front of you, rather than on a public server. If your browser CAN be directed to
http://localhost/ OR to
http://127.0.0.1/, then Apache is awake, if not then the "services" must be started first. Now . . .
You can also try
http://127.0.0.1/[cartaddress]/install/index.php to bring up the OC installer and see what steps are complete. You CANNOT get there by bringing anything up in the browser as a mere "file:|||", THEN the .php files are NOT executable. IF you bring up the webpage while Apache is active, THEN the .php files ARE executable.
If you can't even find the files without using the operating system itself, use that. Otherwise:
Back in square one, inside the OC installation .zip file is a download/ directory containing a config file, and also a download/admin directory containing a config file. Open and edit those, and using your operating system put them where they belong (/config.php, /admin/config.php).
You're just frustrated, take a deep breath and remember, you can get even with it. You can unplug it.