So it looks like they had some tape or something over the red arrow valve. The green arrow valve never popped up, and I was unable to get any psi on the gauge. Once the water came to a boil, a vent of steam (and a bit of water) came out of the red arrow valve.
Can anyone tell me the name of the part that is needed at the red arrow?
I don't have the reputation to comment on your answer. Thanks for the help. The only indication of model or type is "LISTED 409A" on the bottom of the vessel. I'll be sure to get the proper pressure regulator.
Second edit. Actually found the model number. 0178107. 26091G3