another stupid question - should it be placed at the bottom or the top?
@Empress no that isn’t enough airflow and it can cause light leaks. You want your ladies sealed up and no flowering issues or hermies from light leaks. You need the air to circulate inside to prevent molds and mildew. You would put the intake fan at the bottom (at least I do) so the air being brought in is higher in environmental C02. Just leave one upper hole open for exhaust and make sure no light gets in. This is a positive pressure set up and it works for me.
The other way is to just use one exhaust fan in the top and leave a hole in the bottom open for a passive intake negative pressure.
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I agree -At the top. CO2 is heavier than air so you want the flow bring in CO2 rich air at the bottom where your plants are
These are NOT STUPID questions, they are actually good questions that will provide insight to others
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i have the fans now and i ordered a 3n1 ph soil tester. its also supposed to test moisture and light levels. and im going to try the black gold with my next grow. i can see i havent been taking very good care of my babies 
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just closing the top openings (-1) and leaving all the bottoms open has made a difference
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Play with the airflow to adjust your temperature, and remeber humidity will be affected by and affect the temperature, hot air naturally rises etc. To start get you a temperature/Hygrometer that has the remote sensor, that way you have 2 temperature sensors in the tent, 1 to control the fan, and 1 for observation. Using it you can watch the temp/humidity range throughout the day and set you fan appropriately. You want air exchange every 4-6 hours at the minimum. Google the VPD chart for cannabis and set your temp/humidity appropriately.
Tons of information to learn but remember it’s still a weed, and good food, light, water and love will produces some good results.
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