When you log in going forward (or have just completed your one-time set-up), you'll see your dashboard.
The dashboard is made up of three sections. On your left is the Messaging Center where you can see your messages to and from recruiters about jobs in progress. If you see new messages, go to your messaging center to check messages and respond. The second section is Job Applications where you have applied, and the number of new application updates you have. You can then go and view those updates or review past Job Applications. Finally, job postings where you can review your new and existing job matches based on your matching score.
Here you see your messages to and from recruiters. Newest messages are on top. Messages are about specific job postings and either side can end the conversation at any point in time.
Here you see the applications to which you've applied.
This is all jobs to which you haven't applied to in descending order of matching.