You have an HTML form and it will have a name and value for each field such as First Name Last Name etcetera as shown below in the HTML form;
<html>
<body>
<form name='myform' method='post' action='some.php'>
<input type='text' name='first_name' >First Name<br />
<input type='text' name='last_name'>Last Name<br />
<input type='text' name='blah'>Blah<br />
<input type='submit' value='Enter Data'>
</form>
</body>
Then pass it to the some.php with the values that were entered into the form with the following code;
<?php
echo $_POST['first_name']."<br />";
echo $_POST['last_name']."<br />";
echo $_POST['blah']."<br />";
echo "That is all there is to passing the variables!";
?>