Add additional information in backoffice WordPress

Hello WordPress-users,

Does anyone know a plugin to add an information-block to the backoffice pages and post-pages in WordPress. So I can give some extra information (how to use the editor for exampel) there for the editors of the blog?

I already saw the plugin, WP-help, but I’m looking more for an plugin/option to get the information closer to the input fiels in de backoffice pages.

I hope someone has an idea/plugin link.
Thanks on forhand!
Maurice