There is different steps in MRP:

1. Activate MRP in your plant.

2. Create Master Data for MRP (Planning Calender, Quota Setting)

3. Create Material Master with Views like General data 1, Purchasing, MRP1, MRP2, Accounting1.

4. In MRP1 fill the following data (lot size - EX, Reorder Point, Safety stock, Planning Calender etc).

In MRP2 fill the following data (Plan delivery time) and after filling the other views save the materials master.

5. Go to Transaction Code MD03 to run thr MRP.

6. Go to Transaction Code MD04 to view the requirment.