Additional component in Subcontracting

Hi,

I have a simple issue with the subcontracting scenario.

I have a material with its components maintained. If some time I dont have one componenet available with me and want to procure from vendor.

I want to create such a subcontracting order where I dont have one componenet and want to procure it from vendor through the assembly of subcomponents.

Can anybody please explain me how to get this scenario in SAP?

If ther is any configuration required then pls explain.

Thanks in advance.

Regards,

Ashish