How do i create an update query?

Doing Case 3 in Problem Solving Cases in Microsoft Access and Excel, 14th Edition,I believe i have to create an update query based around calculating the difference between 2 dates (move in date and move out date) and if its over 30 days the update query should change the permanent address field to "Yes" under the Rooms Field. the question is as follows:"Create an update query that updates the database and approves a student as a permanent resident when he or she has lived at the home for at least 30 days. The query changes the Approved field to Yes in the table that contains room assignments once a student has lived in a room for 30 days. Save the query as Approvals. Run the query to make sure it works properly and then confirm the results by viewing the data in the Room Assignments table (or whatever you called the table)."