If the module 'Blog display' is still available on your website, you can drag&drop it inside the columns like this:
Select the module 'Blog display' and add it to any of your pages. Then refresh the page and using drag&drop tool, move it inside the columns
If you don't have module Blog Display on your website, there's one tip to add it anyway.
1. In admin mode go to the page where you want to add Blog Display ( you should already have some blog posts) and select Developer tools
2. Inspect any module of your site, in my case I choose the module "heading"
All you have to do is to change the following line using "Edit as HTML":
<button class="btn btn-block btn-link" data action="add" data params="header">
<button class="btn btn-block btn-link" data action="add" data params="blogSelection">
Once done, you click the heading and display your blog posts