This video is a basic walk through of a purchase requisition scenario using and external catalog aka a punch out catalog. This scenario was done with Microsoft Dynamics AX 2012 R3 but this capability has been in the product since AX 2012 RTM.
The setup of external catalogs is done Procurement and sourcing, I don’t cover the setup in this video but you can find a quick overview of that in another post here.
https://organicax.com/2014/08/06/external-catalog-aka-punch-out-setup/
Cheers
Lachlan
OrganicAX 
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