Use split view! When you are on any DocuGen view, click the monday.com settings icon (the gear at the top right corner of the board view), and select Split View. This will allow you to preview the rows that will be included in the generated document.
You can also filter the rows that will appear in your document using the familiar monday.com filter icon at the top of the board view. When you select specific filter values, the split view will automatically show you the rows that will be included in your document.
Want to select specific rows individually? Check out two ways to do so.