not the same question

1) I have a vanity light switch. 2) I have a seperate switch controlling the fan/light seperately; i.e. the fan/light come on together, only when the vanity light is on. I replaced the fan unit but did not pay attention to the old wiring.....a two wire line comes from the vanity light switch. A two wire line is coming up from the fan/light switch (existing)....how do I wire them to get them working w/o popping my breaker?
Thanks