grow cabinet..but i need ventilation idea's

i have taken a metal 6ftx3ftx18in cabinet stripped the selves out and turned it into a room cabinet... but i need ideas on venting it ... im using a 2ft t5 bulb set and i plan on adding another set in th future...the lights dont produce much heat at all...i have taken a 12in fan and mounted it inside the box in the upper left corner facing down to flow air on my plant....do i even need a ventalation system? it so where should i locate the intake and exhaust fans... i was looking at using two 4in "computer fans" for venting if i needed to ...im growing in a closet now with nothing but a fan blowing on the plants...does anyone have any idea?.....

What you need is cool air into the bottom warm air out the top. Been there done that trust me. This allows the natural convection to remove warm air which is a great assist. Do not fight the laws of physics.

check this link:https://www.rollitup.org/indoor-growing/136319-stanley-squirrel-cage-blower.html

I took a fan, any fan, and a hot glue gun, and some dryer hose, and cardboard.
cut a round hole in the cardboard for the dryer hose, hot glue the cardboard to the
back of the fan, then glue the dryer hose to the cardboard. it's easy.