How are you suppose to know which holes to bolt the cleats in?

or where are your feet suppose to be on the pedals? Or which position is better for what?

Thanks

don´t know but I put the cleats on the holes nearest the toes- it just felt better than having the cleats further back

Ideally, the cleat should be centered under the ball of your foot, and angled so that your foot is straight in normal riding position.
If you want to spend money, you can go to a shop where they have the "fit kit" or similar system, and they can dial in your foot position very carefully.
Or, you can just go with what feels good....

Naturally, everyone is a little different, so feel free to experiment.

Center the cleats over the ball of your foot, it's where you'll get the most power. You can screw them into either set of holes (if you've got a four hole nut in the shoe), but center the cleats over the ball of your foot. Also, as for position, notice your natural foot position on the pedals and alight the cleat in such a way that your foot will be close to that position (toe-in, toe-straight, or toe-out). There should be enought float (aka play) built into the system to allow your foot to rotate enough to keep you knee from getting sore.