cant figure this out. help asap

The demand for subassembly S is 80 units in week 7. Each unit of Srequires 1 unit of U. Each unit of U requires 2 units of Y and 3 units of Z. One firm manufactures all items. It takes 2 weeks to make S, 2 weeks to make U, 2 weeks to make Y, and 2 weeks to make z. le Click the icon to view the product structure and the time-phased product structure. Construct a gross material requirements plan (type O if the input box is not used). Item Week 4 1 2 3 5 6 7 Lead Time (weeks) S Gross reg Order release 2 2 U Gross reg Order release 2 2 Y Gross reg Order release Gross req Order release LE 2. Z 2