Hi, ianmac.
The procedure for creating a custom page template is no different for the Salutation theme than it is for any other theme. Just create a PHP file with the required comments at the top, and then whatever code you put in that template will be displayed in the content area of the page, i.e. underneath the header and above the footer.
Note that the Salutation theme already contains [members_only] and [public_only] shortcodes that enable you to display different content to logged-in and logged-out users.
References:
http://codex.wordpress.org/Page_Templates#Custom_Page_Template
http://para.llel.us/themes/salutation-wp/shortcodes/miscellaneous/