With one male goat for a sin offering, to make atonement for you: See the comments on 28.15 and 22. One billy goat had to be sacrificed also during the New Year Festival to purify the Israelites.
Quoted with permission from de Regt, Lénart J. and Wendland, Ernst R. A Handbook on Numbers. (UBS Helps for Translators). Miami: UBS, 2016. For this and other handbooks for translators see here .