Don't get ahead of yourself. This query is not for entering the data, its for setting up the rows where the data will be entered.
So when you run the query, it has 4 records per student, one for each course. It displays only those students in the Center currently displayed on the form and it shows the Month you entered on the main form for all records, correct? If so, then we proceed
to the final step.
Open that query in Design view. On the Design ribbon will be an option to make it an Append Query. Select that Option and it will prompt you to select a table to Append to. You will be Appending to tblStudentProgress. A row will be added to the grid that
says Append To. Some of the columns may be filled in with the corresponding fields in tblStudentProgress. You need to make sure that the StudentID, CenterCode, CourseID and Month columns have their corresponding fields set. I'm not sure if you need anything
else but those four. If you are unsure, list the fields in tblStudentprogress again for me and I'll advise.
The last thing you need to do is add a command button to the main form. The Caption for that button, will be Add Progress Records. Use the Code Builder to add the following code to the On Click event of the button:
DoCmd.OpenQuery "queryname"
Me.subformname.Requery
queryname is the name of the Append query we have saved and subformname is the name of the second subform where you will be entering the scores.
After clicking the button, the second subform should be populated with a record for each student, for each course, for the Month entered. You can then go down the subform, entering the scores.