Once you have tested your site out with https://www.mydomain.com (replace mydomain.com with your own domain), you can redirect all of your traffic to https by adding the following to your .htaccess file located in the public_html directory.
If you don't have an .htaccess file you can create one, if you do have one simply add the following lines:
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
Now everybody that visits your site from a non https link will be redirected to the https version of that page.
If you are not sure how to do this, open a support ticket and we will be happy to place these lines in your .htaccess file for you.