Degassing a Caiman is a function of which version you have. Early ones had a tool that came with the gun that allowed you to depress the valve a little bit (open it) to degass the gun. Mine did not have this tool so I had to contact Utah Airguns who explained why. They put on what I consider a normal degassing screw instead. Getting to it is somewhat involved but once you are there it is pretty simple to degass and adjust the regulator. You have to take both portions of the stock off first. The bottom is a couple screws. The top is held on by tapered pins on early ones but mine has two screws for the top portion too. The scope has to come off to take the top part of the stock off. Another difference is the safety location. Early ones had the safety in the back of the gun but mine is above the trigger. That pin has to come off, however, the safety pin that slides side to side for the lower part of the stock to come off. There are two screws inside the trigger guard that have to be loosened. The smaller one you can access through the trigger guard and it has to be backed off a lot. The larger one is for the tension on the pin and you don't have to loosen it but the pins come out easier if you loosen it like 1/4 turn.
With the stock off, on mine you unclamp the airtube from the rest of the gun. There are two screws at the back of the airtube for this. The degassing screw is under the front one. Open it slowly until air comes out. You may have to loosen it some more to get all the air. Once you are degassed you screw off the back end of the airtube and pull the regulator out. You will need to put a bolt or something into the threaded hole in the regulator to pull it against the O-ring tension holding it in place. I used a tap last time I did this only because it was handy and the right thread. A bolt would be less brittle and therefore a better idea. But you shouldn't have to pull very hard. I don't remember if there is a lock nut but basically you just turn the adjustment screw you will see once the regulator is out. Humas have a paper tape to give approximate settings, I have not seen that on others. 1/4 turn should be safe. To go down, you want to turn clockwise like you would to tighten a normal screw.
It probably sounds more complicated than it is. The only unusual thing is the clamshell stock. I had no instructions the first time I took it off and still got it done.. I assume the first generation Caiman is the same except for no degassing screw on the airtube. I believe the manual has some discussion of how to degass (for the first generation, not the second).