Gallery editing trouble –

Hi all I cannot edit the gallery template (besides editing with Gutenberg, which does not give the desired options). Please can you explain how I can achieve a responsive masonry gallery? The template mentions jetpack, but on contacting catch themes sales support they said I dont need a specific additional plugin. My guess is that this information may be incorrect.. I searched for the suitable jetpack plugin, but also cannot find one about galleries.. Thank you for your help in advance. jana° -- my half finished site: https://maradypi.cyon.site/ see gallery near the top of the home page.