The 1st photo did not show up.
The 1st "tang" should be easily seen on the back of the cylinder. It is round about 1/8" diameter and sticks out about 1/8" It is in line with and right at the end of the key slot on a the diameter and circumference of the circular back of the lock key cylinder. It should be obvious how when the cylinder is turned the tang engages the slot on the shaft.
Sail on silver girl. Sail on by. Your time has come to shine.