You can reset your password through the login screen by clicking Forgot your password (figure 1). Once you have submitted your email address, you should have a link in your inbox.
NOTE! This e-mail can end up in your spam so keep an eye out in all of your inboxes.
When you have received the link in your mail, you click it (figure 2)
Then you can write your new password (figure 3). The password must contain at least 8 characters.