To reset your password, open the login screen and select the reset link under the credentials form. Enter the email address registered to your account, then follow the instructions sent to that inbox to choose a new password. Pick something you have not used before, and store it in a password manager if you use one. Once the new password is saved, return to the login screen and sign in to your account as usual — your balance, bonuses and progress are exactly where you left them.
If the reset email does not arrive within a few minutes, check your spam folder and confirm you entered the registered address, not a different one. When the password is fine but access is still blocked, the recovery routes in the table above point you to the right fix.