When I go to local host, I always get xampp's home page
In the file "\xampp\htdocs\index.php" is a redirect to the XAMPP demopage. Just delete this page.
but I don't know what to do for production,
IMHO a question for your administrator...
If I put 5 applications, what will it happen?
That's your decision.
You can put each application in a different subdir and acces it with "http://server/app1/", "http://server/app2/", ... (without any configuration changes.
And/or you can define different vhosts and dirs for each application and access them with "http://app1.server/", "http://app2.server/", ...