Your manual should have a section discussing this. It's different among brands but if just checking the fluid, it's about the same for the most part.

When checking, it requires you to attain a specific temperature (65 deg C, not sure exactly). Taking it for a quick spin should do the trick, then, let it sit idle for at least a couple of minutes. The dip stick has several grooves and the fulid level should be within the first and the middle (or top if there are only two, I have 3 in mine) grooves. Ideally, it should be closer to the middle (or topmost) groove. Again, your manual should tell you more and it could be different that what I just stated.