PA
a PA is a Program Advance, a combination of 3 or more chips which when selected in the right order, the combine to create a powerful attack yet it can be hard to figure out all of the PA's, so here are some hints
PA's normal follow some code, like the Giga-Cannon PA's (e.g.. Cannon A, B, C or HiCannon B, C, D) ones like this are normally the easiest ones but they must be in alphabetical order, also, you can substitute any of the chips with one that has a * code (e.g.. Cannon A, B, *).
some require a number of different chips with the same code, these come down to 2 different groups, categorical ones and non-categorical ones,
categorical ones are like the Pile Driver PA in Battle Network 4 which requires GunSol 1, 2 and 3 or the Life Sword PA which requires Sword, WideSword and LongSword, these must all have the same code and must be placed in that order,
non-categorical ones are just a bunch of chips which don't really relate to one another like the SunMoon PA (Meteors R, Attack +30 * and Uninstall R), this are really the hardest ones to find because there is hardly any hints to help you find these ones, but are normally the most powerful.
the easiest way to find a PA is either find out some from one of the other Battle Network games or watch Megaman NT Warrior and pick them up from there (Life Sword is normally referred to as Long Sword)