1. Please see https://www.shamimsplugins.com/docs/front-end-pm/getting-started/basic-front-end-walkthrough/
2. Please go to Dashboard > Front End PM PRO > All Messages
3. May i know the purpose of message id in subject? You can enable email piping (https://www.shamimsplugins.com/docs/front-end-pm-pro/getting-started-2/email-piping/) which will add a unique id in subject in email.