Thank you for your post.
I don't have enough information to determine what tables are linked.
If your employee opens a new work sheet, I'm assuming there is an EmployeeID in the Employee table and WorkSheetID fieldin the Work Sheet table, and you have some link between the two tables (WorkSheetID?). You'll need to link the Materials table to the WorkSheet table somehow (MaterialID?). Then, your Employee table will have the ability to see the Materials through the Worksheet table.