Welcome to the guide to the new Minecraft 1.9 Command Blocks!
Step 1: Obtaining Your Command Block
First you need to obtain a Command Block. To do this, you need a command: /give @p command_block 1 .
this gives the nearest player, which is yourself if you are executing this command, minecraft:command_block, or as we know it, a Command Block.
Step 2: Choosing the Type of Your Command Block
Next you can either leave your command block as Impulse, or change it to a Chain or Repeating Command Block. Do so by clicking the top button to the far left, as shown above. Unless you left it as it was, it will change color after you click Done.
Step 3: An Explanation of Conditional Command Blocks
Conditional Command Blocks are almost like Chain Command Blocks, but are still different. They do not need a Chain Command Block pointing to them, but will execute once the Command Block directly behind them executes successfully.
Step 4: An Explanation of Needs Redstone (is It Even Necessary?)
An explanation of needs redstone, it means the Command Block needs redstone to activate, if Always Active, it will activate without redstone, it's rather simple.