In the home workspace, just after clicking 'Change password'.

To change your password, first fill in your old password. The CMS checks that it is really you. Now fill in your new password twice. The CMS checks if they are the same, which means that you did not make any typing mistakes. Do not use copy-paste, because any typing errors would be copied and your password would not be what you think, in which case you would not be able to login any more.