Go to config.php and search for
Code:
$config['page_admin_access'] = array(
under it add your account name, for example,
PHP:
$config['page_admin_access'] = array(
'youraccnamee',
'anotheradminaccname',
);
Or just 1 if its just you.
If thats what you're looking for.
EDIT: After that just go to your page, login to your account go to "My Account" -> Admin News and just add news there