If it's anything like Plat/Gold (which I signed up for only in case of the biggest emergencies), you sign up with your checking account information, there's a fee (I wanna say $5 or $10) per withdrawal plus 3% (again, don't swear to this) that gets pulled "immediately" from your account via ACH pull.

I understand that one can also go into an AmEx travel office anywhere and charge Traveler's checks (and IIRC, Plat and up don't pay the fees), but again, this is from memory from reading that boring blue document (AmEx Cent Bank T&C) that comes when you get the cards.

(I just realized I haven't helped you much. I guess it's time to call Cent CS. )