Take a left short support bar (C) and a right short support bar (B).
Fix the short support bar (C and B) using plug tenon (K) and
plug cover (M).
Take a right long support bar (E) and a left long support bar (D).
Fix the long support bar (E and D) using plug tenon (K) and
plug cover (M).
C
K
C
M
C
K
M
E
D
K
E
D
M
E
D
K
M
B
B
B
x2
x2