Holiday project! Crossbows are very cool to have. Crossbows make several sounds, but not much. The main sound of a crossbow would probably be when it fires, it makes big shot noise. One of the main sounds you might hear if you haven't built or bought a good enough crossbow. That sound would be a snap, which would be the limbs snapping. But hopefully you won’t have to hear that sound. The scope also may make a clicking sound if you have a scope on you crossbow.
Crossbows come in all different shapes and sizes. For example my homemade crossbow is the shape of a normal looking gun. It has a fat sicky-down shoulder rest with a nice curve at the end and a long barrel for the string to have more power to fling and fire the arrow or bullet. Some crossbows have big bits of wood all over the sides of the crossbow but those are rare.
Since there are different types of crossbows they all feel different, crossbows sometimes are really smooth. It would probably be because the people that made it has sandpapered the sides and other parts of the crossbow. Its best not to feel the barrel when you're about to shoot. Your hand would be hurt for days.