To drill a Limestone countertop, follow these steps:

1. Choose the appropriate drill bit: Use a carbide-tipped drill bit or a diamond-tipped drill bit, and make sure it is the appropriate size for the hole you want to drill.

2. Mark the spot: Use a marker to mark the center point of the hole you want to drill.

3. Secure the countertop: Secure the countertop to prevent it from moving during the drilling process. Use clamps or a non-slip mat to hold the countertop in place.

4. Lubricate the drill bit: Apply some water or a water-based lubricant to the drill bit to keep it cool during drilling.

5. Start drilling: Put the drill bit on the spot you marked and start drilling with a slow speed. Increase the speed gradually and apply steady pressure without forcing the drill bit.

6. Check for progress: Periodically stop drilling to cool the bit and check for progress. If necessary, add more lubricant.

7. Finish drilling: Once you have drilled through the countertop, clean up the area around the hole and remove any debris.

Note: Be sure to wear protective gear such as safety glasses or goggles when drilling Limestone to prevent any injuries.