If you find a job listing in the Submissions section that you would like to save and come back to later, click on the three vertical dots immediately to the right of the listing. Click "Add to favorites." This will save the listing in your list of favorited jobs.
Then, click on the button immediately under the profile icon in the upper right-hand corner of the dashboard. Then, choose "Favorite submissions." This will show you every job that you've listed as a favorite.