1. Install the add-on
2. In the dashboard, go to the Attributes page under the Page & themes section
3. In the attributes section you'll see all the attributes associated to the pages: click on the Page HTTP/HTTPS attribute to edit it
4. To enable the addon functionality you have to check the Enable HTTP/HTTPS handling option
5. If your http and https domains are different, check the HTTP and HTTPS domains are different? option and enter the two domain names (no sub-paths, only the protocol and the domain name should be entered): for instance enter http://unsecure.domain.com and https://secure.domain.com
6. Customise the attribute as you wish by specifying if editors too should be redirected (Redirect users that can edit the page)
7. Choose the default behaviour, ie what the add-on should do when the attribute is not associated to a page. Possible values are:
1. Require HTTP: if the site visitors access the page in HTTPS they will be redirected to HTTP
2. Require HTTPS: if the site visitors access the page in HTTP they will be redirected to HTTPS
3. Inherit HTTP/HTTPS from the parent page: the add-on will look for the attribute value in the ancestors of the current page
4. Don't check for HTTP/HTTPS: the site visitors will be able to see the pages both in HTTP and in HTTPS

Once you have setup the default behaviour, you can control the HTTP/HTTPS handling of every page.
To do that access the page properties (either in the sitemap or in the page itself), add the Page HTTP/HTTPS attribute to the page and choose the attribute value from the dropdown list. The meaning of these dropdown values are the same as the ones explained above in the current documentation.