anthony8i:
ok so how can I write a sketch that; say I have led13 on and on my main arduino and second arduino reads if its on or off? or how can I turn the ledpin13 on or of using a switch? gives 1 or 0 on my monitor and the second arduino reads that?
Have you got the switch turning on and off the LED on the first (main) Arduino yet? If not, that is your starting point.
File -> Examples -> Digital -> Button
Get that working.