199:1 The method of burial mentioned in the Torah involves placing the deceased directly in the ground. In many places, the practice is to place the deceased in a casket made of lumber. Since it's impossible that there won't be some holes in the coffin, this is sufficient. There are places where they bury the deceased without a casket, placing him directly on the ground without a board under him, but with two boards on the sides and another board so that dirt will not fall on the deceased, which would be disgraceful to him. In still other places, they bury some of the dead like this, i.e., without a coffin, but for kohanim and first-borns, who are important, they do use a coffin.
When making a coffin, one must be careful not to make any use of the leftover lumber. Rather, it should be used to make the fire to heat the water for the taharah (the purification of the body). Generous people who fed the needy at their table should have their coffins made from the table, as per Isaiah 58:8, "your charity shall go before you."
199:2 The deceased is placed on his back, face up. If someone has some earth from Israel, he spreads a little underneath the deceased and a little on top of him because of Deuteronomy 32:43, "His land will atone for His people." The main part should be placed on the place of the deceased's bris, and on his mouth, eyes and hands.