php - How to pass variables in URL and page? -

my code in index.php:

<?php  $keyword = ($_get['keyword']); $adid = $_get['adid'];  header("location: http://www.tracking.com/base.php?asdf&keyword=&ad=" .$keyword .$adid);  ?> 

the tracking link supposed end with:

&keyword={keyword}&ad={adid} 

i need pass keyword , adid through url onto landing page redirects , pass both variables tracking link.

this url trying:

www.example.com/?keyword={keyword}&ad={adid} 

i don't think can test if format above correct unless run search traffic it.

i need on getting codes right , getting url pass them correctly.

edit: did format url pass variables correctly?

change this

header("location: http://www.tracking.com/base.php?asdf&keyword=&ad=" .$keyword .$adid); 

to

header("location: http://www.tracking.com/base.php?keyword=$keyword&ad=$adid");