This document explains how to use the Manual query type available in the Content tab of the Divi FilterGrid plugin.
Once the Manual query type option is selected, the Include Posts by IDs option will become available. Here you can enter a single post ID or a comma-separated list of post IDs in this field. Only posts with the IDs provided in this field will be displayed in the grid.
This option is not limited to displaying posts. You can use the Manual query type to display posts, pages, or any custom post type.