The website gives specific details of what one should do if there is enough time to prevent significant radiation exposure.
- Get Inside: Get inside the nearest building to avoid radiation. Brick or concrete are best.
- Stay Inside: Stay inside for 24 hours unless local authorities provide other instructions.
- Stay Tuned: Tune into any media available for official information such as when it is safe to exit and where you should go.
- Prepare Now: Identify shelter locations.
The website says if you are outside before a nuclear explosion to take cover from the blast behind anything that might offer protection. Lie face down to protect exposed skin from the heat and flying debris. Avoid touching your eyes, nose, and mouth, if possible. If you are in a vehicle, stop safely, and duck down within the vehicle.
After the blasts remove your clothes and take a shower. Also, the website says that it is safe to eat and drink packaged food items that were inside a building.
You can read more info here