Your instructor can allow you to get partial credit for completing an assignment after the original deadline, but note that second deadlines and partial credit are not a default feature of the system. Check your course syllabus to determine your instructor's policy regarding deadlines and partial credit.
To see the second deadline for an assignment, follow the instructions below.
Locate and select an assignment (PreLecture, CheckPoint, Homework) from the home page
You'll see the original deadline (for which you can earn full credit) in the title bar at the top.
If your instructor has enabled a second deadline (e.g. 80% as long as you submit the assignment by January 5th at 8:00 a.m.), the second deadline and credit details will be visible on the assignment's title bar by clicking the down arrow next to the original deadline.
Second deadlines and partial credit are completely up to the discretion of your instructor, though, and are not a default feature of the system. Check your course syllabus to determine your instructor's policy regarding deadlines and partial credit.