The Day 0 Briefing
Welcome to the wonderful world of Minecraft. It is dawn on Day 0 and you are standing in the wilderness with nothing. Literally. How you got here does not matter, what you do does, and right now what you need to do is find shelter as fast as you can and obtain at a bare minimum around 16 wooden blocks, which you obtain by beating on tree trunks with your bare hands and then walking over to collect when the blocks fall.
Once you have the wood, your next goal is to find shelter, which can be accomplished in several ways. You can either dig up enough sod to build a box with a door you can block up to take shelter in when the sun goes down and the bad monsters come out, or you can dig into the side of a hill to make a cave home and then block off the entrance so that the monsters cannot get to you to kill you.
Let's talk about those monsters for a moment...
There are really just four that you need to worry about right now:
Creepers can be death from above!
a distinctive green-faced mob that will walk up to you, start hissing and then explode, blowing a huge crater in the ground and half your house away if you happened to be standing near it at the time... Creepers are the boogieman in this game, the one monster nobody wants wandering into their house. Trust me on that. It is why you always block the entrance or better yet, install a door.
arrow shooting night monsters who burst into flames when the sun comes up, finding the ashes of a Skeleton usually means finding a bone or two and some arrows on the ground that you can collect for use later.
these guys tend to appear on the roof of your house unless you have built a ledge poking out around it so they cannot climb up there... They are nasty, but during the daytime usually will not go aggro on you unless you give them the stink-eye (look at them) at which point you had better be prepared to kill the thing! They are a source for String (basically their web) that you can use to make things so they are actually worth killing...
they don't only come out at night, but can spawn in dim areas, so you will want to be careful particularly in caves. Like the Skeleton they do not deal with sunlight very well - it kills them.
These guys are covered in more detail in the Mobs Section, but you need the basic info above now, because these are the threats you are facing... Now.
The Basics Controls
Your finger is slid along the visual part of the screen to orient your PoV, and the arrow buttons on the lower left corner are how you move. The button in the center is the jump button, but you will find that usually you automatically jump when you approach a low ledge, so it may only be necessary when the game is not playing nice with you.
Once you get the basic movement and orientation down, and you really should try and do that quickly, you want to look for the place you will make your first shelter - I prefer to dig into the side of a hill but when that is not an option, harvesting sod to build a house with is the way to go - just make sure that you harvest sufficient sod to build the walls AND ceiling, as otherwise you could get a visit form a Spider in the night... Just saying.
Once you have worked out your shelter you need to obtain a supply of around 16 to 20 wood blocks from the nearby trees - but while you are doing that do NOT just go after the tree trunks but also harvest their leaves. The reason for that is really simple - there is a small chance when you harvest the leaf blocks for the brown trees that you will obtain an Apple, which in addition to being a cool thing to have, happens to be food that you can eat to restore health if you get attacked or hurt. And that can happen so having some Apples to eat is a good thing.
Your First Tools
Once darkness sets in retreat to your shelter and seal yourself in, leaving a small opening to be able to tell when the sun rises. Turn some of your wood into Planks, and then make a Crafting Station and place it in your shelter against a wall.
Using the Crafting Station make some Sticks with your Planks and then make a few Wooden Picks - you need those to harvest Stone since smashing it with your fists just smashes it, and does not result in useable Stone resources.
Using Wood Picks you can harvest a stack of Stone that you can then use to make a Furnace and some Stone Picks - you need Stone Picks to harvest Iron Ore, because using anything other than Stone Picks will again result in destroying the resource rather than collecting it.
Iron Ore is the next resources that we want to find, along with Coal, both of which can be found in surface deposits but are more likely to be found underground, which is why the next phase will cover mining, but before we get to that we need to cover some other information first, and logically enough that begins with your Crafting Menus.
So getting with the program here, this guide is written under the assumption that you are playing a Survival game type, and that you understand the basic goals for Day 0. If you do not, then read the following briefing - if you do then skip ahead past it.