Resetting your websites password is relatively straightforward.

To access your site you typically will visit  www.yoursite.com/wp-admin

On this page you ill have a login area which will ask for your username (which is often an email address but could also be a word) and a password. Underneath the password box there should be an option for forgotten password. If you click on this link it will take you to a reset page where you can enter your email address that is associated with your wordpress login and an email will be sent to you with further instructions.