"A" or "ARM on regulator to "A" on generator.
"F" or "FLD" on regulator to "F" on generator.
"B" or "BATT" on regulator to ammeter. Other side of Ammeter to ungrounded battery cable at solenoid or starter switch.
Battery goes to one ammeter terminal. Regulator output and ALL electrical loads go to other side of ammeter.
Polarize generator BEFORE startup
by momentarily jumpering "BATT" and "ARM" at regulator.
If ammeter reads backwards, swap wires between the two terminals.