Using menus

Unbelievably I simply cannot find out where the main forum is to enable me to browse topics to post under!!!!!!!!!

So I hope this will do:

The issue is about menus. I have a menu and a page as a link on that menu. Within that page I link to another page.
Bizarrely that other page which is not a child of and does not appear on the menu, appears on the menu!! The only way I can make it disappear is to make it a child of the main men page, as well as link to it.
But…I don’t want that…I want the page invisible until the link is clicked.
Does anyone know where I’m going wrong?