If you somehow managed to forget your password, the Password reset request form enables you to initiate resetting your password - by providing either your e-mail address (the one you have registered with TSES) or your TSES username.
For security reasons, resetting your password is a two phase workflow.
First step is to initiate the password reset by filling the "Password reset request" form on the TSES web site - either fill the "Email Address" and press the "Request password reset" button next to this entry field, or fill the "Username" field and press the "Request password reset" button next to this entry.
In a second step TSES will generate an e-mail (and send it to your e-mail account) including a web-link which you have to follow to actually reset your password. After this another e-mail will be sent, informing you about to new password for your TSES account.