In this excerpt use context clues to identify what comparison angelou is making with the metaphors of bed as cooling board and blanket as winding sheet.
during the picking season my grandmother would get out of bed at four o'clock and creak down to her knees and chant in a sleep-filled voice, "our father, you for letting me see this new day. you that you didn't allow the bed i lay on last night to be my cooling board, nor my blanket my winding sheet."

burial preparations for after death.

In this excerpt, Angelou describes how her grandmother prayed after waking up. She states that her grandmother would get on her knees and thank God for being able to see another day. Moreover, she thanked Him because He "didn't allow the bed (she) lay on last night to be (her) cooling board, nor (her) blanket (her) winding sheet." What the grandmother is describing are burial preparations. Through these metaphors, she is saying that she is thankful she did not die in her sleep, but instead got the chance to see a new day.