There's a Title (or Top Menu) button on your DVD player remote control. Normally, when a user presses this button, the DVD player loads a main menu, from which you can navigate to other menus or timelines.
If you don't plan on having this kind of menu on your disc, then ignore it. When a user presses that button, they will get a prohibited operation message onscreen. If you do plan on having this kind of menu, link to the menu from Title Remote in Disc properties.
Menu Remote is similar. There is a Menu button on the DVD player remote which normally links to the menu that's associated with the timeline. If you don't care, ignore it; otherwise, link to the desired menu in Menu Remote in Timeline properties.