[Tronixstuff] MCP23017 | I2C Port | Help wanted

not sure I understand the point about the breadboard, I don't see any current at the i/o pin ( using a volt meter) I see a small voltage swing on the power line (the two outer lines on on the bread board, interestingly there is a W at the halfway point i.e. 25 pins left and 25 pins right ) but a current only appears on the lower 25 power line pins. Not sure whats going on here. and what do you recommend for the resistor value?

btw: I was able to get the thie tronixstuff sketch to compile on my mac running IDEv22 but it still the LEDs are all LOW.