Where the shape comes from
A robe laid out flat: the collar folded over at the top and the two flaps hanging below, one crossed over the other in the way a Chinese gown closes. On the left of a character it becomes 衤 and marks cloth and what is cut from it: 初 the first cut of the shears, 被, 裤, 裙, 衬. Its one dot too many is what tells it from the altar radical 礻.
汉字 filed under 衣
No published character on HSK Guide is filed under this radical yet. 汉字库.