In the sent folder of your messages.
When you submit a brief, you can find it in the Sent folder of your messages tab.
Under the Start or Continue Brief section.
If you choose to Save a Brief for Later, you can find the draft brief by clicking the Start or Continue Brief section. All saved drafts are found underneath your existing brief templates.
Under the Approvals List.
If you submitted your brief for approval, you can find its status under the Approvals section of a project. Head to the Projects list and select your project. Under the heading for approvals, you'll see the status of your briefs or deliverables sent for approval. You can also click the blue arrow icon to view more information on all items sent for approval.