Purchasing and assembly

Can anybody send a step by step for ordering an assembly that consist of three internal part numbers to make a assembly internal part number, now it going to be bought externally.
So we have three internal parts in Epicor
A
B
C

They create assembly D
We use to make this internally and now we are going to purchase the assembly externally.

Thanks

Add assembly D as a Material on your job, instead of as a Subassembly. Make sure it is marked ‘Purchase Direct’, and it will be treated as a purchased part on the job, even if the Part Master is set as ‘Manufactured’.

Do you not have a part number for D yet? If you don’t, create one and make it a purchased part. Create a Rev and attach the documentation required for the supplier. Remove A, B, & C from the method and add in D.