Think of yourself looking down on the Solar System from above. As the Earth goes around the Sun the seasons change right? The side of the
Earth that is away from the Sun is the night sky, so as the Earth goes
around the Sun you can see that the night sky faces in different
directions, and you see different part of the galaxy, different stars,
and hence different constellations, and that is why constellations are
The tilt of the earth towards or away from the sun is what gives us our seasons and this both reveals and hides constellations at different
times of the year. For example, the constellation Orion is traditionally
a winter constellation in the Northern hemisphere and dips below the
horizon in spring, only to rise again above the horizon in autumn/fall.
some constellations can of course be seen all year round.
Also for illustration please take a look at this video
and this picture