Change main menu from side menu to a horizontal one

i was wondering how easy is to setup/change the side menu to a horizontal menu. we need to have the subcategories as a list but we do not want the main menu to be on the left side but to be displayed horizontally

Any solutuon?

Greetings,

If you wish all the items to appear in the top menu, rather than categories on the left sidebar, you may set the Template of the items in question to Simple.