Summarize the following:
When a nuclear weapon detonates, it creates a thermal pulse which can set things 20 mi (32 km) away on fire. You can often build a shelter in your backyard if you can position it so that both rainwater and water behind dams runs away from it. You will also need to consider where the utility lines are in your area so you don’t disturb them.  Try to select stable ground where trees and buildings won’t fall on your shelter. If you’re in a city, you can build a reinforced shelter in a basement. The concrete can protect you from fallout and falling debris. Research the topography of your area. Your government’s local land survey office will have them available. Also, check with the emergency response office. Avoid positioning your shelter downhill from bodies of water or below steep slopes. Keep it clear of flammable buildings. Having a clear blueprint will help you construct a stable, effective shelter. You can find some basic plans simply by searching for fallout shelter blueprints online. Some plans may even include a step by step overview for building the shelter.  You can also get blueprints by consulting an architect or drafter. They can provide guidance on what shelter best suits your needs. Most building construction companies can build a shelter for you. Even if you don’t want to hire someone to design a shelter, sketch your own plans before beginning construction. You can try using a computer program like SketchUp. Plot out the shelter’s perimeter according to your blueprint. Plant a series of wooden stakes in the ground to outline the shelter’s perimeter. Then, use shovels, axes, and other tools to dig up grass, trees, rocks, and other debris in the area.  Clear the land about 10 ft (3.0 m) beyond the shelter’s perimeter so you have plenty of space to work with. The shelter’s size is up to you. Expect to add about 3 ft (0.91 m) to the shelter’s length for every person who will hide there. A basic 4-person shelter is about 10 × 10 × 10 ft (3.0 × 3.0 × 3.0 m) in size. Begin digging out soil to form the basic outline of your shelter. You can do this with shovels, although it takes a lot of time and labor. Move the excavated dirt 10 ft (3.0 m) beyond the stakes. You will need to keep the dirt away so it doesn’t fall back into the trench.  For quicker work, rent a backhoe from an equipment company near you. This can get pricey, but speeding up the excavation process is often worth it. Digging a deeper trench means more space and blast protection for your shelter. The emergency exit will also serve as extra ventilation. At the end of the trench, dig a crawl space about 2 ft (0.61 m) wide and 3 1⁄2 ft (1.1 m) deep. The crawl space will be right below the soil’s surface. Create an exit at the end by digging a small trench to connect the crawl space to the outside world.  You can build dirt steps as needed to reach the surface. Pile dirt near the entryway, then begin digging into it with a shovel. Shape the dirt into small steps. Lay threshold boards over each steps, connecting them to side boards with 10 in (25 cm) lag bolts. Always have a second exit in your shelter to guard against emergencies. Create the main entryway the same way you built the emergency exit. This time, dig on the opposite end of the shelter. You can make this entryway a little wider so you have an easier time entering the shelter. Keep the entryway below ground, emerging away from the shelter’s main living quarters. The main entrance will not have air pumps or ventilation pipes running through it, so it may appear larger by default.
Choose a building area on stable ground away from obstructions. Print out a blueprint for the shelter you want to make. Stake out and clear the building area for construction. Dig a trench and move the dirt out of the excavation area. Create an emergency exit at the far end of the trench. Make a second crawl-way for the entrance.