The PP flow consists of planning and execution as described.
Here is the flow of PP in simple language:
First of all demand is generated for the product to be produced through demand management. It calculated the quantities to produce and the time for the final assembly.
The data from demand management is transferred to MRP.
The MRP checks for the availability of material at various stages of BOM. In case material is not available MRP generated planned order and Purchase requisition for production of components in house and procurement from vendor respectively.
Production in charge converts the planned order to production order and carries out the production activities once the order is released for production. Production is carried out as per the operation steps provided in the routing. Work centers are also mentioned with each operation in the routings where these operations are to be carried out.
Once the production is completed production confirmation is done and goods movement takes place.
Capacity planning is yet another part of PP which planes the capacities for various work centers. MPS is another tool which is used to plan out the master products. If MPS is to be run the inputs are provided from demand management to MPS. And the out put from MPS is then feed into MRP.
This is the overall flow for PP.