er - few points:
ordinary bathroom extractors will move hot air out of your growspace, but aren't generally powerfull enough to push air through a filter - so it will do to start u off, but when ur flowering, u will need to step up to an rvk type fan if u intend to use a carbon filter.
to suspend your fans to make them quieter, (assuming it's a 4" - 100mm dia fan) mark & cut a 4" hole as though u are going to mount ur fan flush onto the cupboard side.
Knot a thick elastic band through each side of the fan housing & hang it from the ceiling of ur growspace.
Stuff the ducting through the hole & duct tape / jubilee clip it to the back of the fan - simple.
Makes a big difference to the noise output - almost stops it completely.
Don't for get u need a bend in the ducting or u will see light thru it
If u don't have any ducting, make some with rolled up wallpaper, then glue a cereal box to the side where the duct exits, leaving the bottom of the box open.
(obviously cut a hole in the front of the box for the vent to poke thru!!!)