在Wordpress中打开自定义页面URL

I can't seem to get a simple additional page opened in Wordpress. I have in my theme directory a file called contact.php. How do I get tag to source this page? Ideally it'd look similar to the below:

<a href="<?php get_template_directory_uri('contact'); ?>"> Contact Us </a>

If i were to use Wordpress's Page setup I'd have a huge block of code similar to:

if (page == contact) {
    return contact form
} elseif (page == about) {
    return about me page
} else {
    return the regular page format.
}

Do the following instead:

<a href="<?php echo get_template_directory_uri() . '/contact.php'; ?>"> Contact Us </a>