After creating your assignment you'll be taken to the assignment overview page, from here click on the Settings tab to get to the assignment settings.
Here you can adjust all settings by clicking on the sidebar (seen in the image below).
Details: adjust your assignment title and description
Submissions: specify types of submissions
Feedback: adjust the number of reviews
Groups: allow group submissions
Categories: create submission categories
Rubric: allow preview or weighting
Advanced: disable flags or change anonymity