Patio Door lock

Hello i am a 21 year old handyman from winnipeg, manitoba, canada i am new to locks and don't know where to find the parts or whole assembly, it has a dual hook latch and a lock knob that passes through the assembly and a small c clamp that keeps the lock knob from pulling out. the shaft of the lock knob is keyed on both sides. 2 screws pass through the interior handle the lock knob and passes through a metal framed patio door and to the exterior handle. the lock latch metal piece slides up and down but there is nothing on the lock knob to rotate the lock latch into engaging any help would be great !!
Best Regards
Austin