the maester's path setup clarification

By SSJ_Vis, in 2. AGoT Rules Discussion

i haven't seemed to be able to find any post or notes on the attachment setup whether you choose an attachment thats face up on the agenda or face down randomly. how's that work exactly?

SSJ_Vis said:

i haven't seemed to be able to find any post or notes on the attachment setup whether you choose an attachment thats face up on the agenda or face down randomly. how's that work exactly?

Anyway, if you were to put the cards on the Agenda face down, how are you going to prove to your opponent that they are Chain attachments?