First time kegging help needed

Ok so I have a 2.5 gallon keg that I transferred my beer into and I chose to use priming sugar for this time. It has been sitting for a month now. I know for a fact it did carbonate as I have LIGHTLY pulled on the ring and definitely heard air come out. So now I am ready to chill and try my first attempt at pouring. So what do I need to do from here. Chill obviously. Connect CO2 obviously. Then what? Do I purge what pressure is already in there? Or do I just simply connect, find the right PSI and start attempting to pour until right PSI is found? Any help will be greatly appreciated. Thank you

Ice

1 cool keg, 2 tap beer, at this point you can see where your carb % is at to much foam vent a little not enough connect your co2, since you naturally carbed. I wouldn't hook to co2 right away, I tap a few first then hook up, or you can vent keg completely connect to co2. I like to compare the two there is (to me) a taste difference.