To change HTML/PHP code you can edit core files of component (not recommended) or use Joomla Template Override system to override only views, like we did for articles, portfolio etc.

Tips:

1. Create new folder inside current used template: templates\shaper_TemplateName\html\com_spkgarten
2. Copy there all (or selected) folders with files inside from components\com_spkgarten\views
   and then inside those folder, you can safe edit all files, components views.