OHS are used as a warm-up at the start of a session and before any ‘snatch’ based exercise.
These are great to feel your way in to the deep squat, receiving position in a slow and controlled manner. Only 2-3 sets are normally required before progressing to the more dynamic movements like snatch balance.
Often used in CrossFit, lifters need to be careful with this movement to only load it once they have grasped the position. The shoulders should remain in a neutral position with the back nice and straight and the lifter sitting upright with their heels remaining in contact with the floor at all times.
As a lifter with considerable experience myself, I never loaded this exercises more than just an empty bar. There was no need. The loading overhead came from more dynamic movements once I was properly warmed up. Too often in the last few years have I seen and heard of CrossFitters loading overhead squats to a closer too or even more than they could snatch and wondering why they end up with elbow and should injuries.
Like with any lifting movement, it takes time to develop the overhead strength and stability required to load this exercise to please be careful.