Pretty much the title.

I'm sure this has been asked and answered ad-nauseam by now - did you not find an answer when you searched for relevant threads before posting this?

In any case, the answer is simple.  Put a picture of the moon on the middle of your ceiling (add constellations if you wish).  Now walk from the "southern hemisphere" to the northern hemisphere on the opposite side of the room.  What do you observe?

If you continue to have trouble understanding beyond that, I encourage you to visit grand central station and observe the model of the earth and sky that the main hall represents.