I suggest you post this question again in the bonsai section, because that is essentially what you are doing. Cypress trees can get quite big. They are often grown in containers, but very large like 10 gallon ones, not on top of the desk size.
But they are a relatively slow growing tree and if you keep it in the small pot, you can bonsai it, ie stunt its growth so it stays little in the little pot. But there's an art to that to keep it from just getting overcrowded and pot bound and dying.
But to start with, yes the pot has to have holes and let the water out. Otherwise the soil stays wet all the time and the roots rot and the plant just dies. Put a saucer under it to protect your desk, but don't leave water standing in the saucer. Let the soil dry out a little (the top inch or so) between waterings. Make sure it has plenty of light -- a desk lamp would probably help it.
PS... welcome to the forum, glad you found us!