During the Submission stage, the editor checks the submission files to decide whether it should begin the peer review process. Some submissions may be clearly inappropriate and never make it beyond this stage.
When you log into your Dashboard, you can find active submissions either from your Tasks, or from one of the queues (My Queue, Unassigned, All Active, and Archives). The counter gives you an overview of how many total items are in each queue.
When viewing a submission the editorial actions available are:
Send to Review: Send the submission on to the Review stage, where it will be reviewed by peer reviewers.
Accept and Skip Review: Send the submission forward to the Copyediting stage if you'd like to skip the peer review process completely.
Decline Submission: Remove the submission from consideration and archive it.