Some people have difficulty in using redstone because they don't much about it, now I will teach you what I know

Part I: Items

Redstone: A wire that connects your creation together.

Redstone Repeater: A block that extends the reach of redstone. Also used for timers very often.

Redstone Torch: A torch made powered by redstone that emits a redstone signal.

Redstone Comparator: A block that can compare and maintain certain blocks.

Redstone Block: A block that emits a redstone signal, mostly used with sticky pistons and pistons.

Lever: A switch that you need to flick back to shut down.

Button: A switch that shuts down automatically after a few seconds.

Pressure Plate: A plate placed on the ground that emits a redstone signal when walked on.

Piston: A block that pushes a block or an item by one block when turned on.

Sticky Piston: A block that pushes a block by on block when turned on, it also sticks to the block so when it retracts, it stays.

Redstone Lamp: A block that emits light when turned on.

Command Block: A block that does a specific command when turned on.

That's pretty much all you need to know for the items.

Part II: The most important part

The most important part is to have fun. Play around with the redstone, make some experiments, and you will be able to.