Here "he" refers to the one making the offering. It can be stated in second person. AT: "Then you must kill the bull" (See: [[rc://en/ta/man/translate/figs-123person]])
It is implied that the priests would catch the blood in a bowl as it drained out of the animal. Then they would bring the bowl with the blood in it and present it to Yahweh at the altar. (See: [[rc://en/ta/man/translate/figs-explicit]])
As indicated in 1:9, the person must also wash the inner parts and the legs of the animal with water. The person would do this before giving the pieces to the priests so they could place them on the altar. As in the UDB, you can state here the instructions to wash the inner parts and legs. (See: [[rc://en/ta/man/translate/figs-events]])