To display your marker it is required to attribute it to categories and tags.
You can choose Category (1) from All Location Categories (1.1) or add New Location Category (1.2 & 1.3). Tags (2) are similar to categories. Add new Location Tag (2.1) or choose one of most used tags (2.3). Attributted tags are under most used ones.

You can manage categories and tags in Location submenu.