The tutorial is on adding a new Webmaster user role which comes in between your site Administrator and Editor. This user is same as site Administrator but it excludes some capabilities like managing plugins, changing themes. Users with this role will not be able to install or activate any theme or plugin. They can change the widgets, edit theme options like background, header images etc if your theme provides and do all other things which a site admin does.
Simply install and activate Webmaster User Role. After activation you can assign its new role called ‘admin’ to your users by editing users from Dashboard -> Users -> All Users list or while adding a new user in your website.