Within the awareness message template you have the ability to manually send out all awareness mails by clicking on the start button. If you click start, all awareness mails will be sent immediately. This option is only available, if you did not select the option to send the mails automatically in case of a successful attack. In case you want to send them manually and you don't see that start button, deselect the option within the scenario settings "send mails automatically" (your campaign needs to be stopped to change the settings).