Redstone is something that what you can do is limitless and it is kind of like the technology of Minecraft. If you understand Redstone then you understand how to make cool things happen with a click or flip of a button or lever.
To understand Redstone you must first know the basics like how to power things, you can use a lever or button or pressure plate. Once you know that then get Redstone dust and connect it to the power source and flick in the dust will turn bright red. If you did it right connect it to something like a piston and it will activate pushing a block. It is like self opening doors and wires.
It is how you power thing you stick some redstone dust in a thing and it powers. It need to be powered by a power source. It will run out of power and about 14 blocks.
It extends the power of redstone dust. It can also slow thing down based on the tick.
It is the most important redstone item ever, it allows redstone to push blocks. This is a regular piston, there is a sticky version.
This is the sticky piston.
I am not going to state all the redstone circuits here, go to the Wiki for more. Or go to the credits, I have a link to the wiki there.