NB: You will need a very little rudimentary html and CSS knowledge for this. Also you'll need to be familiar with the xenForo navigation manager.
This is a beta. There are known issues, e.g. the code that creates the hover on dropdown stops the submenu overflow link list at the top of the node...
Add a mega menu tab to your navigation with some extra features.
DEMO on customizexf.com
set position of mega menu tab on bigger screens (as first navigation tab or as the last one)
set position of mega menu tab on mobile (as top navigation tab or as the bottom one)...