I'm at a standstill due to bathroom wiring dilemma!

I have opened up my bath with studs and ceiling exposed. I have one power source going into the room. I have a: 1. VENTILATION FAN/Light/Night light 2. 3 switch for one gang box 3. Vanity light that I wish tied to Main Light in Fan 4. Separate shower lights 5. Single switch for shower lights I have new 12/3 wire and 12/2 wire. I know I'm going to split the power source to the shower light switch and to the 3 switch. Can someone look at the diagram below and tell me how to wire the 3 switch to the ventilation fan with a the power line.