My generic for the ducting: . Use straight pipe (metal or PVC) whenever possible, wrapped with insulation and a vapor barrier. Corrugated, flex pipe creates turbulence and has almost double the surface area for water exhausted from baths to collect on. Use as few bends as possible with 45*s instead of 90*. Tape metal joints with silver tape, not duct tape (4 year life). Tape the individual joints of each elbow. Use 3 screws on each metal joint. Use HVAC black tape for plastic covered insulation. Insulate the whole pipe and the fan box.Use caulk to seal the small gaps at the fan to wallboard joint. Don't drill through any floor joists, rim is OK.
Be safe, Gary