Mixed Layout: 2 Small Posts, Followed by 1 Full
In order to show your blog posts in a grid format, go to Appearance > Customize > Blog Feed and change the Post Display Format.
This is a mixed format display and shows two posts in one row (side by side) followed by a full format post. So if you have set your settings to show 6 posts (“Blog pages show at most”) in the blog feed under Settings > Reading, then they would be shown as: 2 side by side, 1 full, 2 side by side, 1 full.
If you use the “more tag” you can control how much content is visible in the blog feed and the user can click “more” to view the complete post.
Click here for a demo.
More on the different post layouts can be found here.