I wasn’t aware of the Gallery module template provided by Quark…
Looking at the Changelog of Quark, it refers to the lightbox-gallery plugin, which is a paid Premium plugin. Which means that without the paid Gallery plugin, the template won’t do much.
If you do consider buying the Premium plugin, all questions about the plugin and other Premium products should be directed to GitHub - getgrav/grav-premium-issues: Official Grav Premium Issues repository to report problems or ask questions regarding the Premium products offered.