How to apply saturation setting on only a selection on Photoshop Ipad ?

[Voilier Bleu]

Hi,

it's really simple to do that on Photoshop  : Make a selection, go to the menu, set saturation and it will only apply on the selected part of the selected layer.

How to do exactly the same thing (i dont wanna mess with other stuff like mask of layer technics...) on photoshop ipad ? I use it a lot in my work.

Thanks for your guidance.

[Voilier Bleu]

As i've got no answers, i eventually decided to cancel my subscription to Photoshop.