I am currently working on blog page for a custom Wordpress theme. This page consists of all the posts available in thumbnail format. You click a thumbnail, you go to that post. I know how to do a basic post loop so every thumbnail shows. I also know how to add HTML within that loop. However I need to know how to add a div ONLY after the first post is placed. The first post that's placed should be the latest post, thus the largest. Next to that I need another div that has nothing to do with the posts.

How do I make a loop that places a div ONLY after the first post. Then continues placing the other post thumbnails. See the image below.

[![enter image description here](https://i.stack.imgur.com/mkeYE.png)](https://i.stack.imgur.com/mkeYE.png)