How do I know when I can submit my assignments to the Dropbox?

In the upper left scarlet navigation bar, there is a Dropbox link. Click it. On this page you will see a list of Assignment titles followed by "Deadline: date," if assignments can be submitted, or "Opens: date," if they cannot. If there are no deadline restrictions, there may be no date at all. The Assignment title will be linked if submissions can be made.