Help learn2 nav

I am using learn2 theme and i have many pages, but i only want see current open page and its child on nav. Can you help me?

Maybe a little sketch would help to know exactly what you mean?

all pages that i have, it will show at sidebar of learn2 theme, but i only want title of pages that i opening which will show at sidebar while others will hiden

in the sidebar partial (https://github.com/getgrav/grav-theme-learn2/blob/develop/templates/partials/sidebar.html.twig#L7-L21) you can add a conditional to this for loop (http://twig.sensiolabs.org/doc/tags/for.html#adding-a-condition) that ensure the loop only iterates up to a certain level. data_level is 0 for top level, 1 for second level, etc.