Portable CO2 refill kit instruction:

Screw in the big and small CO2 tank to each ASA adaptor of the refill kit (Make sure the valves on the adaptors are turned off by turning them counter-clockwise a few turns) Turn on the small CO2 cylinder by twisting the on/off valve at the end of the cylinder counter-clockwise a couple of turns.   3a. If the big CO2 tank does not have a siphon tube inside (eg. reg 12oz or 20oz CO2 tank), hold it upside down and turn the ASA adaptor valve on the big tank clockwise until it stop. 3b. If the big CO2 tank has a siphon tube inside, you don't need to hold it upside down while refilling since the liquid CO2 will be forced through the siphon tube in the big tank to the small cylinder.   Wait about 1 minute for the liquid CO2 to transfer from the big tank to the small cylinder and for the pressure in both tanks to equalize.   Turn off the ASA adaptor valves (counter clockwise). Turn off the on/off valve on the small cylinder (clockwise).