Hello,
1. First off, the resistors are supposed to be labeled 75ohm, 33ohm, etc. instead of 75R, 33R, right?
As Mike says, Yes.
2. The elements labeled 1, 2 and 3 are light-dependent resistors. What about the relay, is it an SPST relay? If the author instructed to use a 9V relay, would a 12V relay work too?
Its single pole single throw relay
You may have to reduce the 33R in the darlington emitter.
I'll have some more questions a little later...Thanks for taking the time.