Email notifications are sent as email. they are sent once each day and will contain a collective of all the email notifications that were activated for you that day.
When you receive email notifications they will look like this:
From here you can either submit your journal entry for that video by clicking on the link 'click here to submit your entry now'. That will take you to a screen like the one below where you simply type in your journal entry and click submit.
Team leaders and coaches get the notifications as above when users complete their field exercises and they can enter coaching comments via notifications.