The 'Orders' table would be like this:
Code:
OrderID
CustomerID
SheetMusicID
PurchaseDetails
PurchasePrice
ShippingPrice
...
So the three tables 'SheetMusic', 'Customer' and 'Orders' are connected. You can make different queries on 'Orders'. e.g.:
List all orders of a title:
Code:
select a.* from Orders a, SheetMusic b where a.SheetMusicID=b.SheetMusicID and b.Title='my favorite song'
(Just a fake SQL)
Just some thought on database design, I have no Access coding experience, although I worked a lot on other databases.