how to say or design a template, about m if connected do this if not do this

dbconnect.php
<?php
$host = 'localhost';
$user = 'root';
$pass = '';
$dbname = 'mydatabase';
if($mycon = @mysqli_connect($host, $user, $pass)){	page will coonect to the server
//echo 'connected to the server';	priunts perfectly connected to server
if(@mysqli_select_db($mycon, $dbname)){	connects to data base
//echo 'connected to the DB';	if perfectly connected, it prints, perfectely connected to database
} else {
//echo 'DB connection failed';
} }
else {
//echo 'server connection failed';
}
?>
With require and include, we can get the variables used in that template and results also

@mysqli_connect

@mysqli_select_db

if if else else how to connect to  server how to connect to data base