NOTE: Schemes Linked to Main Categories become transparent to the entire tree under it (subcategories, 3-rd level categories). If you for instance link "Business" scheme to Main Category "Business  Opportunities", all subcategories and 3-rd level under category "Business Opportunities" would inherit this scheme. The same is true when you link a scheme to subcategory - all 3rd levels under this subcategory would inherit the linked scheme. However, if you're linking a scheme to some subcategory, this scheme will take precedence and be selected over the scheme linked to the main category above it when ads are posted under this subcategory. The same is true for 3-rd Level.

In other words start from the top, linking the scheme - mostly used throughout categories on your board to Main Categories and work your way down linking other schemes to subcategories and 3-rd levels.

If you create a new subcategory/3-rd level, is does not automatically inherit a custom scheme from Main category (if linked) and will stay "default" until you explicitly create a link. To save the hassle, create a complete categories structure and then start linking schemes.

For more info see: Admin Help