Thank for your fast response
The first screenshot is how i want to be
The second is how is it now
Anyway, I'm moving this to the Themes forum...
The theme is the klassroom theme.
I contact with the creators of the theme and send me here. Here is the answer
This query is related to moodle not related to theme. Actually moodle made this feature. So you can create your query here https://moodle.org/mod/forum/view.php?id=50 moodle developer/community people can help you.
Ok, the link the theme developers have given is to the general forum here, which is where I believe you first posted. However, given your screen shots where you want to remove a column on a given page then that will be a part of the layout (layout file or called mustache template) - it could be a block region. Thus it is a specific theme issue for the developers to help you with. As even though themes have a common structure, at the fine detail level, each one has specific changes pertaining to them only. Please contact them again and do make reference to my post.
Thank you very much Gareth. I'll do it and if it need i return.