In T5, go to http://yourdomain.com/accounts/login/ or http://yourdomain.com/dashboard to get to the log in screen. On this screen, there's a link to reset your password
When you click this link, you'll be taken to the password reset screen where you can enter your email address.
Once you enter your email address and click on Reset my Password, you'll get an email sent to you with a link to reset your password.
The link will take you back to the website where you can enter your new password.
Click Change my password to save your new password. Click the Log in link to log in with your newly reset password.