Speak of the devil?...
Best tip for a first time user is to not get carried away, which is very easy to do!
You'll have to decide what type of system you'll want to run, direct port, or single point (often referred to as a "wet" system). The TBI intake is designed to have fuel go through it, so a "wet" system is ok, the only real problem will be distribution to four ports from one injection point. Mounting the nozzle up as high as is likely practical should help in this regard.
As for controls, run, at a minimum, an arming switch, and a full throttle switch. If the car is a stick and you're prone to bogging it, a RPM switch would be a good idea, as it will prevent the system from coming on at too low of a RPM, which can cause damage due to the high pressure such a high concentration of nitrous can produce.
There are lots of "goodies" that you can add to any system, but most aren't going to be a requirement in order to actually use the system, most are convenience items or things that make the system more "automatic"/consistent.
If you choose to use a RPM switch, I'd suggest looking at the NOS mini-Controller, it has a RPM window switch built in, can trigger off the TPS signal and ramps in the power however you set it to, and for less than $250.00... Some RPM switches will cost more than that by themselves.
As to AFR. 12.5:1 is a good starting point, but a little richer is ok, so long as you're not getting a lot richer. If you want/need to dial things in closer, you'll need to read the plugs, I don't trust sensors to give me the whole story when things get a bit more "critical".
Speaking of critical, the most critical aspect of a nitrous tune-up is going to be ignition timing and fuel, due to detonation concerns. As for fuel, run the best you have available. As to timing, retard it from where the engine runs its best on its own about 1.5-2* per 50HP added. This is a safe starting point, often engines will like a bit more timing than this, but running "too little" timing will only kill power, not engine parts!
Now for the $10K question... "how much can I run?"... You can "pill it up until you sweep it up, then back it off a bit", or keep it to about 40-50% of what the engine was designed to make from the factory. Most engines are "over-built" enough to handle that amount of added power, some can handle much more, some not so much, but those are fairly rare, and not in the Mopar universe thankfully.
Feel free to ask if I've left something out that you are curious about.
Mike