in Magento 1.x you could duplicate the extensions to
app/design/frontend/themeName/default/template/or/layout and then modify it's layout or functionality via xml or phtml files.
How do we duplicate and edit certain modules now in M2? I have looked over the docs but couldn't find this info. For example i wish to edit phtml of
module-catalog/view/frontend/templates/product/gallery.phtml correct way by having theme based module overwrite and now edit core modules within
Thanks for the help.