1)
What follows the head?
1.
Radak: The head is the Keruv; the Ofanim go after the Keruv, for "Ru'ach ha'Chayah
1
ba'Ofanim" (1:20).
2.
Radak citing Targum Yonasan: "Ha'Rosh" is the first [direction in which they go; they do not turn from it].
1
The Keruv is the Chayah (15). (PF)