To reset or change your password you must be logged out of the dashboard. If you are currently logged in then go to 'Settings>My Account' and click on 'Logout'.
On the 'Log in' screen push the 'Forgot password?' button located under the log in form.
Type in the email address you use to sign into the dashboard and click on 'Reset Password'.
Check your email. You should have received a 'Password Reset' email. Follow the directions in the email to reset your password.