add_submenu_page

There seems to be various posts on this, but I can’t seem to find the answer to what I need.

I’m writing a theme and want to have a top menu, along with sub-menus in admin.

I’ve sorted it out so that a sub-menu (Colour Settings) shows up, but when clicked on, it just shows a blank page, though the first page (when the top menu is clicked on) shows up fine.

This is what I have:

add_menu_page('vShare Theme', 'vShare Theme', 'administrator', __FILE__, 'vshare_settings_page', 'favicon.ico');
	add_submenu_page(__FILE__, 'Edit', 'Edit', 10, __FILE__, 'section_edit');
	add_submenu_page(__FILE__, 'User Guide', 'Colour Settings', 10, 'coloursettings.php', 'userguide_settings_page');

I was trying to have it all on the same page originally, but couldn’t figure out how to separate the different sections, where to place functions, etc. I ran out of hair in the end.