Honestly I'd start by talking to your suppliers, and asking them what/if they have in place. If they have nothing, ask them if they can put together something to explain their supply chain, key controls (e.g. certification etc).
I say this as someone who has spent (wasted?) many hours trying to shoehorn my supply chain details into one-size-fits-all templates sent to me by customers.
If the purpose is genuinely to understand what your supply chain looks like, and what key (authenticity?) risks and controls are in place, then I'd always go for a good discussion to arrive at an agreed-upon format for each supply chain type, in preference to a generic mapping document.