Assuming you're referring to the stove top and not an actual griddle:
The first thing you want to do is make sure your stove top is cooled completely to avoid any accidents. Once it's cooled, you'll want to remove any loose debris or burnt on food. The best way to do this is to use a putty knife or razor blade to scrape it off. If there's anything stubborn, you can use a little bit of elbow grease and a non-abrasive cleaning pad.
Next, you'll want to apply a thin layer of vegetable oil to the surface of your stove top. Use a clean cloth to rub it in and then buff it off. This will help to keep the surface seasoned and protected.
If your stove top is particularly dirty, you can make a paste out of equal parts baking soda and water. Apply it to the surface and let it sit for 15-20 minutes before scrubbing it off with a non-abrasive cleaning pad.
Once you've removed all the dirt and grime, you'll want to apply another thin layer of vegetable oil to help keep the surface seasoned. Use a clean cloth to rub it in and then buff it off.
And that's it! With just a little bit of care and cleaning, you can keep your Samsung stove top looking like new.