Its a pill that ive always had to fill at any pharmacy. They will prescribe you take it from a certain day starting with the onset of your period. Some Dr's do days 2-6, 3-7 or 5-9. Taking it earlier normally results in more follicles but not necessarily as mature, while taking it later suggests a more mature follicle. Some women have some side effects including headaches, and sore breasts. I suggest taking it at night, you can take it any time of day but be consistent with the time.
Clomid wont necessarily induce ovulation. If you're seeing a specialist they might do a monitoring ultrasound to check follicle sizes.