Removing notification bar from a specific page

You could add css to the landing page to hide it.

#wnb-bar{
display:none: important!;
}

What if I wanted to remove it only for logged in users?

This would have to be programmed in.

I am a begginer, where I should add this command exactly? thank you

Just add it to the page or post you don’t want it to show. You’ll need to wrap it in style tags.