10 Jun 09 12:31 am
Approaching your questions in the order you asked them:
The robustness and flexibility of the themes is dependent on the developer of a particular theme. It sounds like the person who developed the theme you are using primarily intended it as a 3 column layout, and removing the third column was an after though.
Your options here are to choose a different theme, or to edit the current theme to suit the layout you want.
Most of the Wordpress themes - like the default layout - have a navigation menu (either down one side, or across the top are common). These navigation menus include a "Home" button, but also automatically list your site's Pages so users have a way to get to them.
If you don't want your pages listed, you will need to find a theme that doesn't have a navigation menu, or edit the theme to prevent it displaying your pages.
Hint: if there are tabs across the top, you will probably want to edit the Header (header.php). Look for wp_list_pages( ... );
To add a privacy page to your site you will first need to create the privacy page. Choose a slug such as "privacy". You should then edit your theme's Footer (footer.php) to include a link to the privacy page.
Note: To edit your theme login to the admin area, then in the menu under Appearance, select Editor. You will need to be a fairly capable HTML and PHP programmer to edit a theme.