First things first, ganache is a mix of cream and chocolate. It is the truffle center for all of my truffles. I am going to be making 15 different flavors of ganache this week. I personally do:
1# dark chocolate
1 1/2 cups cream
All you need to do is chop the chocolate into small pieces, no larger then a half inch, then place it in a heat proof bowl. Next scald your cream with a pinch of salt. As soon as the cream boils pour it over your chopped chocolate. Let it sit for 1 minute then whisk until it comes together. Be careful with your whisking. I tend to splash cream all over the counter, which is kind of a waste of deliciousness. Once you have thoroughly combined your chocolate let it sit at room temp for at least 10 minutes then refrigerate until set. I like to make it a day ahead. Now you have made ganache!
Once the ganache has set I like to use a 110 size ( the smallest) ice cream or candy scoop to scoop the truffles into equal portions. Then I roll them into little balls just like you would tollhouse cookie dough before you bake it, except much smaller. After this I either put them back into the fridge, covered, then dip them into tempered chocolate or you could just roll them in cocoa powder and call them done and delicious!