All women and girls (or, if there isn't a woman in the house, the head of the household), light candles at least 18 minutes before sunset – see this link for the exact time – and recite the following blessings:

Transliteration of the first blessing:
Ba-ruch A-tah A-do-nai E-lo-hei-nu Me-lech ha-olam a-sher ki-deshanu be-mitz-vo-tav ve-tzvi-va-nu le-had-lik ner shel [if Yom Kippur is on Shabbat add: Sha-bat vi-shel] Yom Ha-Ki-pu-rim.

Blessed are You, L‑rd, our G‑d, King of the universe, who has sanctified us with His commandments and has commanded us to kindle the light of [if Yom Kippur is on Shabbat add: Shabbat and] Yom Kippur.

Transliteration of the second blessing:
Ba-ruch A-tah Ado-nai E-lo-hei-nu Me-lech ha-o-lam she-he-che-ya-nu ve-ki-yi-ma-nu ve-hi-gi-ya-nu liz-man ha-zeh.

Blessed are You, L-rd our G‑d, King of the universe, who has granted us life, sustained us, and enabled us to reach this occasion.

If the one lighting the candles intends to drive to synagogue for the Kol Nidrei prayers, she should have in mind while lighting the candles that she is not just yet accepting upon herself the sanctity of the holiday. She should then immediately proceed to the synagogue, without undue delay.