I would start at ground and the work up to that. Sounds like you still have to dismantle your dresser and build the door light proof. Generally light proofing is the hardest step for most.
Start with a pencil and paper: list and draw. Possible air ports, cord port(s?), location of light hanging apparatus, height/width of growing container(s?)/(soil or hydro?), scrog net supports (if going that route), etc.
Lots of ways to power a CPU fan, from a 5v-12v wall wart, an actual AC/DC fan controller and a hacked computer power supply (great for running many fans).
If you click the search in the top right, and search thread titles "dresser", you'll find lots of inspiration.