Whether you are using WordPress or WordPress Thesis Theme, loging into wordpress is the same for either themes. You simply need to type your url plus /wp-admin in the browser. For example if your web address is http://lowcostwebsitesolutions.com you simple need to at /wp-admin like so;
This will then take you to the login screen for the WordPress Dashboard. WordPress will remember your user name and password for your next visit. This is a short but sweet wordpress tip hope that it helps.