Reveal children current menu

Showing just the immediate children of the current menu item is fairly straightforward : Branch = Current Item, Starting at +1 (children), For Depth 1 level.
Shortcode equivalent:
[cmwizard menu=NN branch=current start_at="+1" depth=1/]

If you want to also show the current item, then leave Starting at set to its default value (“the Branch”) and change For Depth to 2 levels.
If you want to show any ancestors of the current item, then either configure them (under Inclusions), or change Starting at to an absolute level … depends on exactly what you want shown.

Thanks @wizzud for your answer !
Do you know how can i hide item which is not current ?
Example :
Item 1 / Item 2 / Item 3

Submenu : item1-1 / item 1-2
item2-1 / item2-2
item 3-1 / item 3-2

I click on item 1 to open item1-1 & item 1-2
I would like to hide as well item2-1, item2-2, item3-1, item3-2
I would like an accordion submenu like in this page : https://urlz.fr/2hY4

I hope to be clear in my explanations :/

Unfortunately I think things are becoming less clear from my point of view.
By introducing accordion-style menus, I think you are now talking about presentation, not content, and that is beyond CMW’s remit. Any styling and/or interactivity that you wish to place on the menu is down to your theme, and possibly other plugins that can accordion-ise a menu for you. CMW does not provide any styling … at all! It can modify the output HTML slightly if you configure it to, but that’s it.

Fine i’m going to search other plugins to customize my menu !
Thank you very much for your help and reactivity !

Have a good day ??

No problem. I hope you find what you need.