You will need:
Take inspiration from natural forms such as shells and pebbles
Start by carving the overall shape. Don't try and remove too much material in one go or you might break off a chuck. If this does happen, don't worry! This sometimes happens to sculptors with natural carving materials like stone and then they have to adapt their design.
Experiment with your different tools to see what different textures and marks you can carve.
Make sure you keep turning it round as you are carving so that you can work on all sides.
When you have finished your scuplture think about how and where you would like to display it.
You might like to display it alongside the natural forms that inspired you.
If you and your friends or family made several sculptures you could create your own mini sculpture show. Will you display them outide or inside? You could take some photos to share.