Install the FastenMaster TrimTop using the square drive bit enclosed.
Predrilling is typically not required for cellular PVC decking and trim.
It is always recommended to predrill when fastening within 1 ½” of end of any board.
Predrilling and countersinking is required when fastening into hardwoods like Ipe and mahogany or fastening into frozen deck or joist boards.
Use a 1/8” drill bit for the pilot hole with countersink.