Nitrous is dead simple mate.
A simple explanation - Nitrous produces oxygen, its not flammable, so when you inject it and it gets heated it produces Oxygen. That Oxygen won't make any changes to the engine other than slightly more compression and throwing off the A/F ratio so you need to inject more fuel to compensate for all the extra oxygen the nitrous reaction has given you. (just warming nitrous up sets of the reaction, hence bottle heaters giving more pressure etc etc)
This is where the power comes from, the extra oxygen produced by the nitrous allows you to burn more fuel. Thats why you have a nitrous and fuel solenoid.You also need to make sure the fuel gets there before the nitrous so you normally put a loop in the nitrous line to the jet and run the fuel line straight to the jet.
The ratio of nitrous to fuel stays the same, you just need to make sure you don't put too much of both in or not enough of one or the other, that website has some of the best guides as to how to meter the fuel & nitrous. But if your doing it yourself, over fuelling is safer than under fuelling. And start with the smallest jets, always. And use your spark plugs to get information about whats going on inside the cylinder as well as an Air to fuel meter.