Could someone explain me how to perform this problem, please?

Problem 9-18 (Algo) Product A is an end item and is made from two units of B and four of C. B is made of two units of D and two of E. C is made of two units of F and two of E. A has a lead time of one week. B, C, and E have lead times of two weeks, and D and F have lead times of three weeks. b. If 120 units of A are required in Week 10, develop the MRP planning schedule, specifying when items are to be ordered and recelved. There are currently no units of Inventory on hand. (Leave the cells blank, whenever zero (0) is required.) 2 5 10 Item: A OH: 0 LT: 1 SS: 0 Q: L4L Period: Gross requirements Scheduled receipts Projected available balance Net requirements Planned order receipts Planned order releases Item: B OH: 0 LT: 2 SS: 0 Q: L4L Gross requirements Scheduled receipts Projected available balance Net requirements Planned order receipts Planned order releases Item: C : 0 LT: 2 SS: 0 Q: L4L Gross requirements Scheduled receipts Projected available balance Net requirements Planned order receipts Planned order releases Item: D OH: 0 LT: 3 SS: 0 Q: L4L Gross requirements Scheduled receipts Projected available balance Net requirements Planned order receipts Planned order releases Item: E OH: 0 LT: 2 SS: 0 Q: L4L Gross requirements Scheduled receipts Projected available balance Net requirements Planned order receipts Planned order releases Item: F OH: 0 LT: 3 SS: 0 Q: L4L Gross requirements Scheduled receipts Projected available balance Net requirements Planned order receipts Planned order releases