WM staging/consumption of handling units for the process order

Dear all,

Can some one tell me the standard SAP functionality process flow, to be able to pick Hu's for a process order and PGI them with reference to the process order?

The process order has both Hu-managed and non-Hu managed materials. To stage the HU-managed material in the process order, what steps should I perform in the system?

Thanks in advance!!

Anjali