You should see such a text on screen when you hit
"www.yoursite" or "www.yoursite/main_Q2A-dir" :
Welcome to Question2Answer. It's time to set up your database!
[blah blah blah]
Create Database including User Management.
Do you see it ?
If not, check if you configured qa-config.php correctly.
Then check if ANY php file is executed properly on the server. E.g.:
echo "this is test ! ";