Check out a theme called Magazine Basic. It has a grid format. You could probably hack his style sheet to figure out how it’s done.
Check out my site at https://www.desertdogjournal.com for an example. There is also an option for three across.
Template shows the first image as a thumbnail, title is hyperlink, and includes an excerpt or first part of the text. Sounds like just what you want. Template has php files for each option so you just need to find where the call out is in the CSS and copy that into your template.
