I’ve never succeeded in growing it from seed, though others have. I buy some of the live basil plants at the grocery store, gently separate the plants (there’s like 4-12 actual plants per pot) and plant them in potting soil or compost in a pot that drains or in the ground. Keep the soil moist and the light bright, not direct sun if you live somewhere hot, though. Works great for me!

There’s a special way to harvest your basil that will make it grow more and you should always pick it this way (just above paired sets of small leaves):