The board comes with a ribbon cable to attach to the main PCB, the ioboard clips in on right I think (been a while) D1&2 are your +- volts, speaker isn't used if your not using a speaker , the bell output can be used but all depends on current draw of the alert sounder
Maybe someone else can comment
Resistor is normal there because the speaker and bell being used same time
Any reason it must be these Sounders?
The zone on the Io board and be programmed as the tamper