Baby leaves, yes. Once the leaves get full-sized they're a little too bitter to eat raw.
I basically use it as a spinach substitute. It's good sauteed in a little butter with salt and pepper, or used in soups, or chopped up in omelettes or fritattas. You'll just want to cut out the big central rib; it's pretty fibrous and not pleasant to eat.
I love Swiss chard, and it's very good for you! I hope you find you like it too. :)