For the starting feature just hold the brakes for at least 5 seconds and its activated. Hold the breaks for 10 minutes and it'll still do the full power launch.
Punch level 4 is reactive map that "adapts" the drive frequency to high rpm, low rpm, and everything in between.
I don't know what level corosponds to what "map", but I like the most punch I can get in stock so I keep it at 5 when I'm running that, then play with the punch when I'm running mod. Usually I run it at level 1 or 2 when I'm running mod off road. Wether thats the "right" one for mod offroad I don't know, but I just play it by feel.