Step 1:
1: Attach D to B by using H1, H2, H3 separately as right diagram
shown. Do not fully tighten
2: Attach C to B by using H1, H2, H3 separately as right diagram
shown. Do not fully tighten
(H1) x 4
M6*
20
bolt
(H2) x 4
M6
spring
washer
(H3) x 4
M6 washer