It is visible in the northern hemisphere during winter and early spring.
To find it:
1. Locate Orion. It's easily recognizable by its three stars in a row that form Orion's belt.
2. Look to the north-east of Orion's belt. You'll find two bright stars relatively close together, marking the heads of the Gemini twins, Castor and Pollux.
Let me know if you'd like more details about the constellation Gemini!