1. Once ashore, make sure that you go far enough from the water that there’s no danger of it being taken away by any waves.
2a. When you set the kayak down, set it on sand or grass. Make sure that the rudder doesn’t touch the ground, digging a hole if need be. Don’t place it on rocks or asphalt, as they will damage the hull.
2b. You can also place the kayak upside down, with the hull topmost. But if you do that on a beach, you risk getting sand into the cockpit.