Point 1 (Lu-5) :
Observe the faint crease that represents the elbow joint.
Now bend the elbow by about 45°.
You will find a rope-like structure at the centre of the
front surface of elbow. This is the tendon of the biceps muscle
of the arm.
Point 1 Lu-5 lies on the elbow-crease,  just near this tendon
(on the outer i.e., thumb side).

Point 2 (Lu-6) :
Joint points Lu-5 and Lu-7 with a straight line.
Point 2 Lu-6 lies on this line, five thumb-widths below the
elbow-crease (i.e., point 1 Lu-5).

Point 3 (Lu-7) :
This point Lu-7  lies on the outer border of the forearm,  two
finger-widths above the wrist joint.

Point 4 (Lu-9) :
This point lies at the outer (i.e., thumb-side) end of the
wrist-crease.