Yom Kippur 2017 -- details about what is means for Jews? (Chabad dot-org)

Yom Kippur is the holiest day of the year, when we are closest to G‑d and to the essence of our souls. Yom Kippur means “Day of Atonement,” as the verse states, “For on this day He will forgive you, to purify you, that you be cleansed from all your sins before G‑d.”1
It is held on the 10th day of Tishrei, coming on the heels of Rosh Hashanah (the Jewish New Year, which is on the first and second days of Tishrei).
For nearly 26 hours (in 2017, from several minutes before sunset on Sept 29 until after nightfall on September 30) we “afflict our souls” by avoiding the following five actions:

• Eating or drinking (in case of need, see here and consult a medical professional and a rabbi)
• Wearing leather shoes
• Applying lotions or creams
• Washing or bathing
• Engaging in conjugal relations

Like Shabbat, no work is to be done, and special holiday candles are lit before the onset of the holy day.

www,chabad.org/