@Vale71 hit the nail on the head in post #3.
If you just want to putz around, there are threads linked in here that are a good starting point; however, don't expect to come out on the other side with a better-than-commercial NA beer. In other words, set your expectations low! I would not waste your time with heat extraction. You might as well just throw a few dollars on the ground and set it ablaze...save yourself the headaches.
With that said, if you are okay with 0.5% and above then it's a different game altogether. You need to choose a style that can withstand what happens when you "thin" out a beer (adjusting grain to water ratio). Sours are very easy to work with because most of them are fruited, and the complexity of the fruit and the souring agent is enough to make a 0.5% beer something you'd go back for a second and a third. While they lack the heft of a 5-8% sour, they can pack a nice flavor punch.
I managed a wheat beer once, and I may try to replicate that in the near future. Again, I just needed to adjust the grain to water ratio and the hop ratios. I found that dialing the hops in is the biggest challenge though (half is a good starting point, but it's hit and miss depending on the hop and its current AA%). I've also made hop water that could be used to clean some rusted tools, or whatever other application you could dream up for super bitter hop water...poisoning people maybe? In other words, my suggestion is to brew one large batch, and then split it out with three different hops levels until your system is dialed in. From a personal choice perspective - I only use a small amount of bittering hops and adjust in dry hopping.
And last but not least, brown ales are good down to about 3%. Anything lower and it becomes a meh beer...I mean, they're not bad, but they are far too thin. Again, just adjust your grain/water ratios until your gravity is at a point that it'll finish out at 3% or so.
I gave up on pale ales (too hop driven), and I don't drink IPAs (hop oils do not agree with my sickly gi system).
I'm happy to answer any questions that I can, but my method is about as simple as you can get. I want the brewing process to be the same whether it's a 0.5%, 3%, or 7-8%, and that's what I've been able to accomplish by adjusting ratios. It's not an end-all-be-all, and there are certainly better methods (?), but they are all going to be more complex than the basic adjustments I make.
K.I.S.S.