This guide is to explain as much as possible about Minecraft PE. I definitely cannot explain every single thing, but I can explain enough to get you started, and teach you most of the info on Minecraft. There are several different subjects, in this order:
Creating Worlds
World Types
Game Modes
Using Options

Step 1: A Whole New Wooooooooorld...

To create a new world, first press play on the home screen. Click the "NEW" button on the world screen, and choose your options. Then click play. To exit the world, press pause and press "EXIT WORLD".

Step 2: World Types

There are three types of worlds:
Old
Infinite
Flat

The first type is Old. Old worlds are the average world. It has trees, biomes, and villages. It is a bit faster than the Infinite world type, and the world is a certain amount of bricks wide.
The second type is Infinite. It is exactly the same as old, except that it randomly generates new areas of land when you go to the edges. The other thing that's different is that sometimes, Infinite is slower because of the random generation of new areas.
The last type is Flat. Flat is, well, flat. There is a flat layer of grass going infinitely in all directions. Bedrock is only four blocks down, and you can only use this Flat in Creative mode.

Step 3: Game Modes

There are two game modes:
Creative
Survival

Creative is where you have infinite blocks, you cannot be killed, and monsters do not spawn. Lastly, you can fly in creative. To fly, double-tap the jump button. To stop flying, double tap again. In the inventory, the windows are as follows:
Tab 1: Food/Plants
Tab 2: Tools/Transportation
Tab 3: Decorative Blocks
Tab 4: Building Blocks

Survival is where you have to find/make your items. You can be hurt, and monsters spawn and attack. In the inventory, the tabs are as follows:
Tab 1: Armor
Tab 2: Crafting
Tab 3: Inventory

Step 4: Choosing Your Options

The options from top to bottom are:

Tab 1: Playing Options
Name: Changes what other players see as your name.
Difficulty: Whether monsters spawn and you heal in survival.
Third Person View: Makes you see yourself from the back while playing.

Tab 2: Controls
Sensitivity: Makes it easy it is to look around.
Invert Y-Axis: Makes you look down when you swipe up.
Lefty: Moves the controls to the right side of the screen.
Split Controls: Centers the screen controls on the middle of the screen.
D-Pad Size: Makes the D-Pad larger/smaller.

Tab 3: Graphics
Brightness: Makes the screen brighter/darker.
View Distance: Changes how far you can see in the distance.
Fancy Graphics: Makes the graphics fancy.
Beautiful Skies: Adds clouds and stars to the sky.
Animated Water: Makes the water look like it's moving.

Tab 4: Volume
Sound Volume: Changes how loud the music and the sound effects are.

Step 5: Crafting

I'm just going to show the basics:
Wood Planks: 1 Wood Block
Crafting Table: 4 Wood Planks
Once you have a crafting table, you can place it and use it to make tons of objects. Such as:
Furnace: 8 Stone Blocks
Once you have a furnace, you can make
F.(stands for furnace)Charcoal: 1 Wood Block
F. Iron Ingot: 1 Iron Ore
F. Gold Ingot: 1 Gold Ore
Torches: 1 Charcoal, 1 Stick
(Place all over your house so that monsters don't spawn)
Door: 6 Wood Planks
Axe: 3 (Items), 2 Sticks
Shovel: 1 (Item), 2 Sticks
Sword: 2 (Items), 1 Stick
Hoe: 2 (Items), 2 Sticks
Pickaxe: 3 (Items), 2 Sticks
Chest: 8 Wood Planks
Shears: 2 Iron Ingots
Bed: 3 Wood Planks, 3 Wool Blocks

Step 6: Mining

The first thing you need to know about mining is that you need a pickaxe. For creating a pickaxe, you first need a crafting table (see Crafting). Once you have a crafting table, for you to make ANY kind of pickaxe, the recipe is:
|X|X|X|
| |Y| |
| |Y| |
X=Item
Y=Stick
The types of pickaxes you can make, from weak to strong, are:
1. Wood (can mine stone & coal)
2. Stone (can mine iron & what wood can)
3. Iron (can mine gold, lapis lazuli, red stone, and what stone can)
4. Gold (can mine diamond & what what iron can)
5. Diamond (can mine everything)

To make a mine, there are many different ways. Everybody has preferences, but the method that I use most often is this:
1. Dig a few blocks into a mountain.
2. Then, dig the two blocks in front of you.
3. Finally, dig the block below the ones you just dug out.
4. Step into the hole you just made.
5. Repeat steps 2-4

Step 7: Farming

To farm, there are three things you always need:
A Hoe
A Bucket of water
The plants

The steps are simple:
1. Hoe grass
2. Dig down one block next to hoed grass
3. Place water in hole
4. Place plant on the hoed grass
5. Wait

If placed pictures of the plants before and after they've been grown (above). Once they're grown, you can hoe the plants and plant the extra seeds.

Step 8: Enjoy!

That's it! If there's any subject you all want me to add, go ahead and write a comment! If you like this instructable, please vote for me in the Minecraft Challenge!