Menu that open up to menu links

Hello Everybody, Attached is a screen shot for the "Help menu" for Service Studio. I need to implement the same functionality of the menu and that is the user selects a category. The category opens up to several links. If anyone knows how to do this....please do tell.
Check out the Directory App that you use from outsystems App "samples".
They use Department and Department Units.
On my point of view, you need to have an entity that stores the "Main" category.
Then, have another entity, with all the links, with a MainCategory attribution so when the user selects whatever category, you go to the next entity and get all the Links that are related to that category.
Not sure if this is the best approach, but it's an idea.

Just found this, didn't looked through it, but looks like it's something like this that you want.

Thanks again Francisco!!!   That link was exactly what I am looking for.  Perfect.