If you want to use lemongrass in a soup or curry it is really quite easy. Lemongrass comes in stalks about a foot or so long. Lemongrass stalks shouldn’t be brown but rather pale yellow turning into green as you get towards the end. Strip away the dry outer leaves, cut away the stumpy end and the dry leafy ends. Chop each lemongrass stalk into 3″ pieces. Next you want to bruise the lemongrass to bring out the aroma. To bruise the lemongrass bend the stem a bunch using your fingers to stimulate the juices and even make a few cuts in the stem.
Lemongrass is great for Thai curries, soups or stocks. Here in Vancouver I can find lemongrass in the produce section of most grocery stores. Also, if you want to store it it freezes quite well so if it is hard to find in your location you can always buy lots when you see it.