Please open the page you want to be the Essential Grid Blog page. Choose the page template “Default”, “Blog” wont work in this case since it would remove all manual content.
Next step is to include the Essential Grid via the Visual Composer element.
A new window will pop up where you can build the grid on the fly.
We recommend using a predefined grid (available in the dummy content install tab of the theme options).
Otherwise please select “Recent posts” and follow the instructions given in the Essential Grid documentation: http://themepunch.com/essential/documentation/#quick-grid