match is winning a free credit if the last two digits of your score are the same as the two digits that light up on the backglass after the game is over.
the adjust plug for match is on/off, and it needs to be in the on side of the socket for the lights to turn on at game over.
internally, the match number is selected by the 00-90 unit, and that unit steps whenever either of two playfield rollover switches close. You don't see what two digit number it's selecting until the game is over, and it's a pretty good bet the numbers don't go in sequence so people couldn't count the number of rollover switch activations.
if you want to see the match number sequence, manually step the 00-90 unit after the game is over and watch the lights.
"chute" is referring to the coin chute(s). You may not have more than one, but a typical game had two and you could configure them to give different numbers of credits for a coin. Typically it'd be something like one chute is 10 cents and the other is 3 plays for a quarter in the USA.
high score adjust is winning free games for getting certain scores. It's also adjustable whether you get a credit for reaching a score or an extra ball. Below I'll just say credit to mean either.
the high/low two pin plug selects whether the range for winning is 11,000-110,000 or 101,000-199,000.
the details of the score setting socket at the top of page 1 gives an example of putting the plug with the red wire into the 1000 position of the socket. That'll give you a credit at 31,000 or 131,000, depending on the position of the high-low score adjust plug.
btw, "drum" on the schematic = score reel.