After the world is generated, do some exploring. The first thing that you'll need is wood so chop down around 3 trees and you'll get maybe 11 blocks of wood. Then in your inventory convert all of the wood blocks into wooden planks in the little crafting area. While your walking around collect anything that may be of use, for example cacti for a home protection system of some sort.
Step 2: Step 2: Food and Shelter
With the wooden planks that you just crafted you have to build a shelter to protect yourselves from the creepers. Really if you happened to miss step 1 then you can dig a hole and bury yourself alive. If it is Night time now then go into your house and wait the night out. If it is currentley day time then go around the general area of your new home for some animals for food (pigs,e cows and chickens). and if you want to cook your food just make a furnace and cook it up with wood as fuel.
Step 3: Step 3: Tools
Now you need to make your basic wooden tools: a wooden pickaxe, axe, and shovel so that you can cut down trees, mine, and dig stuff.
Step 4: Now You're Ready!
Now is the time to Fight Back, Mine some Diamonds and play some Hardcore Minecraft!