Use a master-detail pattern to show a list of items and allow users to select an item to see more of its details.
Provide a link from the top-left corner of the details view to return to the list of items.
Don't use grid row selection checkboxes to display an item's details. Checkboxes are used for selecting one or more items in order to take action on them.
Don't display an item's details below the grid on click. For tall grids, users may not notice the details loading below the fold and may think the UI is broken. Additionally, there's no clear indication that the new section of the UI is showing details of the selected item.