A Foolish Question That Shoudn't be asked...

But how do you equip and fire a crossbow in Diablo 2??
I am a Newbie to the game, {Behind the times, Yes, but I want to know}
If I equip a ranged weapon on my character he won't shoot!!
What do I do with the arrows??? {And what are the bolts for??}
{This is probably very obvious, and doesn't needed to be asked, but oh well, tell me what I am missing.}