All of the assignments you've made or saved for the future, including mastery goals, can be found in the Assignments tab.
You can view your assignments two different ways, depending on what is most useful for you. The By assignment view lists all assignments in order of due date, beginning with the one soonest/farthest in the future and in descending order. This is helpful to keep track of what you've assigned to your students.
The By student view lists your students and their assignments, with assignments also ordered by the one due soonest. This is helpful for when you're trying to view student progress, grading, or checking assignment completion in class.
You can edit or delete assignments by selecting Actions > Edit/Delete.
If you have assignments that you've saved as a draft but have not yet assigned, you can access them by clicking the Saved tab.