Adding Required Imputs to this page

[Zer0Cam]

Ok, I designed  a ticket system and I want to add a field for  How would I add this so there required to put in the name and room number

 

*Teacher Name: [ Box here]

*Room Number: [H11]

 

URL: http://test.geekinc.info/index.php?page=ticket_submit

 

[marcus]

if(!$_POST['submit']){
echo "<form method=post action=thispage.php>\n";
echo "Teacher Name: <input type=text name=tname><br>\n";
echo "Room #: <input type=text name=room><br>\n";
echo "<input type=submit name=submit value=go>\n";
echo "</form>\n";
}else {
$teacher = $_POST['tname'];
$room = $_POST['room'];

  if($teacher && $room){
  //do this
  }else {
  //not supplied
  }
}

[Zer0Cam]

Were would I put this? In the file that that page is in? And were?