I strongly disagree on the setup with only one fan. Having only an exhaust fan in the room will draw nasty air in through cracks in the house's structure, possibly stuff with e.g. mold spores. My wife could never remember which way was which for our window fan; I could tell by smell when she had left it exhausting for more than an hour.

If you have only one, set it to intake and leave another window open a bit (maybe like half the fan size). You can confirm that air is exiting that way by hanging some strips of tissue paper in it.

Positive pressure (blowing in, from outdoors) is also the right thing to do if you are trying to keep smells from other rooms at bay. Whereas negative pressure (blowing out, to outdoors) is best to keep a smell confined to one room (e.g. this is how bathroom fans work).