Antimatter Theme: Subpages

Complete beginner here. I am using the antimatter theme (with slight customizations) enable through theme streams/inheritance and want to know how to get drop downs for subpages similar to the "Layouts" in the OER Skeleton http://demo.hibbittsdesign.org/grav-oer-content-space/

The OER demo is using Gantry5 theme framework to achieve those different layouts - http://gantry.org

However, you can do similar with any Grav theme by creating a variety of top-level page templates. For example, Antimatter already has a few like default.html.twig, blog.html.twig, etc. Just create a new one for each 'layout' you want to create..

Regarding dropdowns, Antimatter already supports that, just enable it in the Antimatter theme configuration. https://github.com/getgrav/grav-theme-antimatter#menu-features

A perfect. I was trying this but was activating the drop down in the wrong file (have sorted it out now!) Thanks for the quick response!