Set up your assignment in canvas. They encourage you to star the assignment name with "Extra Credit".
Set the points to zero. This will alert Synergy that it is an extra credit assignment.
You can put it in any canvas category. I picked Participation, but it doesn't matter.
Make sure you click the box for Sync to SIS and set the due date within the grading period.
Publish the assignment
You may now award up to 200 points for this assignment. Anything over 200 will not work in Synergy.
When you log into synergy, it will say Extra Credit for the assignment in the gradebook. Notice it still says pts as 100. This is fine since it's set as Extra Credit. You'll notice I only awarded 5 points for my assignment. That's why it says the average is 5%.