There appear to be 2 methods in your documentation for priming the 3880 carts:
1: The video has you pulling the white plastic lug from the side plug, inserting the syringe without needle or any other extension, withdrawing a small amount of liquid, then closing the plug (checking that the cart is primed).
2: The document provided has you fitting the priming tip at the end of the needle-less syringe, uncapping their air vent (orange lug), and inserting the syringe into the prime ink feed hole at the front of the cart, and withdrawing a small amount of ink as above.
I used method number one and assume it hasn't caused any problems or damage because flush went very well. Could you please confirm, and advise your preferred method.