Remove any tough outer leaves from the lemongrass and cut off the bulb. Thinly slice lower half of stalk (the upper half can be discarded OR cut into long segments and added to the curry pot for extra flavor). Mince the slices with your knife or pound with pestle & mortar.
Time-saving Tip: Instead of using fresh lemongrass, substitute 3 Tbsp. bottled OR frozen prepared lemongrass (bottled lemongrass can be found at some supermarkets, or look for the frozen type at your Asian food store).