How do I stop porridge sticking to the pan?
I keep it on low heat after I've gotten it up to boiling initially.  It will stick sometimes, but after I stir it, the stuck stuff will be reabsorbed into the water.  I try to get as much stuff as possible unstuck when stirring, and then a moment later the remainder will have magically become unstuck.  I guess it sticks because the water rises and the oats precipitate down to the bottom of the pot; conversely, it magically unsticks because the stuck oats get reabsorbed into the water.  I find it's okay as long as I stir it every few minutes.

I turn the heat off after a bit, usually when big, slow bubbles start to balloon up or it just looks like it's thick enough.  At this point it won't be totally thickened, but it will have absorbed enough heat to make it the rest of the way, so I just let it sit on the stove for another 10 minutes or so, maybe more.

I also go 2:1 water:oats.. actually a bit more water than that, probably 2.2:1.  This is partly to compensate for the small amount of water that will boil off even though the lid is on when I'm not stirring it.