Please, I really need help with the following ERD design.

In the following ERD, it is shown that a customer places an order at POS. The salesman(Employee) checks for the order's availability from a warehouse.

Now I want to add a scenario that: "If the ordered products are not available then the Employee orders those products to be manufactured and supplied to warehouse for availability".

Now I cannot figure out if the Employee would order to the branch manager and then branch manager would order the supplier for raw materials or if the raw materials are already available then just proceed with the manufacturing of the order(i.e. first the branch manager would first check for the availability of raw materials before ordering to the raw material supplier). Now is this the job of manager or the Employee at POS(salesman). I just can't figure it out.

Please help me develop the given ERD and also provide an explanation.

DraW RAW MAETRIAL SUPPLIER Ware House (stock of the completed products for sales COPY OF Draw COPY OF Draw Smart Draw DELIVERY transporting OF RAW raw maetrials ATRI MATERIALS Check Availability of the ordered Products etting the delivery from ware house after nvoice generation shipmen of order ADE TH A TRIAL CO Smart Dr Customer Collects his/her order after generation from MADE TH A TR POS Smart Drew Storage Unit MADE WITH A TRIAL COPY OF EMPLOYEE(at OS MADE TRIAL COPY Sales, POS and Inventory maintanence,payment generation and invoice clearence OPY OF Custome MADE WITH A TRIAL COPY OF Smart Draw SmartDraw Manufacturing of Manufacturing materials, testing Plants AL COP MADE materials SmartDraw Routing(Providing material for work centers) MADE WITH A TRIAL PY OF Smart Dora Inventory Details Update MADE MADE Smart D Work Centers productio units in plants) MADE WITH A TRIAL COPY OF MADE Smart Draw