@MarthaSosa Welcome! I'm not sure what the teacher is looking for exactly from that statement, but I suspect that they would like to filter assignments by quarter and/or turn off sync for past quarters automatically.
First you need to setup grading periods for the correct terms. More instructions can be found here.
Grading periods allow teachers to filter their gradebook and their assignments page by the grading period(s) that you set up. For example, if you're on a quarter system, you'd set up the grading period to include when the quarter starts and ends, and then the teacher will be able to filter by grading period, pulling all assignments with a due date between the quarter start and end.
Once you set up the grading periods you should be able to go into Settings and check the Automatically disable 'post to SIS' on assignments when grading period closes checkbox. This will allow Canvas to shut off Sync to SIS.
Hope this helps!