While there is no built-in setting to make those columns, there are many ways to do this using CSS. You might want to look into CSS flexbox and/or CSS grid.
It looks like your developer has already modified the core theme files, so you might as well make any future changes in the CSS file at
In general, it’s usually a good idea to avoid editing the core theme files since future changes to the Curatescape plugins may require theme updates. Instead it’s recommended to either use the built-in “Custom CSS” theme option (see Appearance > Configure Theme) or to create and include (in
/common/header.php) a separate CSS file that will override the default styles with your own customizations. This will make future maintenance easier.
Also note that hosting your site in a subdirectory (i.e.
glassborohistory.org/digitalarchive) can result in errors with the popout menu (which your developer appears to have removed, possibly for this reason) and the image viewer script (not currently working). Instead, it is recommended to host your site in a root domain or subdomain (e.g.
Of course, these recommendations are not requirements, but I wanted to let you know for future reference. Hope this helps.