i dont know what it has in the istructions that come with the kit.
but i've run quite a few bottle of NOS through my car over the years, race track stuff only.
if i was adding say 100hp of NOS into my motor, it needs about 80% of the volume of gas that your putting in, extra petrol at the same time to stop them running too lean,
not sure if i have explained it too well though.
if you wanted to keep using it, i'd recommend fitting a power jet into your carby.
something like this, but jetted down a touch.
http://www.ebay.com.au/itm/160656368612?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
NOS is basically a cylinder filler, it helps to create more pressure in the cylinder, and gives you a bigger bang when the fuel ignites.
when you have it all set up, if you want to check it, give it a tiny bit (a 1/2 second burst) at mid throttle, the revs should increase a bit.
then when you want to give it a bit more of a try, make sure you only use it at wot, for about 2 or 3 seconds
then shut it down and do a plug check.
if it looks ok, try it again for a couple of seconds more, and check it again.
you may need to fit a colder plug so it doesnt melt them