obviously, menu structure is kept in some db table that you could manipulate directly if you can't find how to do it in monox api reference

you can use the admin console btw, then go to pages and on the right is the menu tree. Items you check at the grid on the right appear at the menu

don't think they've implemented drag-drop, from grid on the right to tree on left side unfortunately, can only drag in tree to reorder

need to checkmark pages at the grid to show them in grid

renaming at tree changes menu name, renaming at grid changes page title

at tree can add clickable toplevel menu items or nonclickable ones (called folder items) that are useful only to host child items that show in dropdown menu