$aPagesTypes = Array( 1 => 3, 2 => 4, 'page_ID' => 'Type of left menu' );
This code includes information about which page should displaing which menu. In example page with ID=1 will display "Subcategories 1" menu and page with ID=2 will display "Subcategories 2" menu.. You have to first add some pages and after that connect them with types of menu.
4. Change name templates/menu_3.tpl for templates/menu_left.tpl, delete templates/menu_4.tpl and in templates/container.tpl delete variables $sMenu3 i $sMenu4 and in place of them paste variable $sMenuLeft
Last thing which You have to do is change templates/menu_left.tpl for Your needs. Should works fine..