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Attach the cove molding to the bottom base of the newel post. This section is often easier to attach as the base itself provides a natural shelf for the molding to rest on. Apply a continuous bead of wood glue to the back of the cove molding. Carefully align the molding piece, ensuring it sits flush and creates a clean, finished transition. Secure the cove molding in place using a brad nailer. Look at the joints from above to make sure they are perfectly lined up, as this is the perspective from which they will be most visible.