Yes, the pressure is CO2 pressure from a bottle.
You probably need to replace the O-rings on the cover and fittings. Northerbrewer.com sells kits for that if your kegs are like mine.

To make stout you just follow the recipe, like any other brew. It just takes a little longer to ferment.

The American Pale Ale I just made is as simple as it gets. 10# of crushed 2 row barley, 1.5 ounces of Cascade Hops, Safeale US-05 yeast.

Get a brewing book to show you how to get the sugar out of malted barley. HOW TO BREW by John J. Palmer is a good one. Brew-Master's Bible by Stephen Snyder is also good.

After extracting the sugar from the grain I steal a cup and add a cup of cold water to it. I add the yeast to that to get it started. You bring the rest to a boil and add 1/2 the hops. Boil for 45 minutes, add the other half and I put in a tab of wirllock to help with clarity. Boil for another 15 minutes, chill the wort down to 110F (I use a beer chiller) and add enough water to make 6 gallons in the fermenter. Add the yeast and close up the fermenter, put on the bubbler and let it go for a week. Transfer the beer to a clear carboy with an air lock to get the beer of the yeast and to allow the beer to clear. On week 2 it goes in the keg for a couple of days of cold conditioning at 30#, then turn the regulator down to 5# to serve.