how does redstone work in minecraft?

Answer 1

It's a bit difficult to answer this in full, but you can check out the wiki, which is all I needed to learn. You'll find the basics here and a more advanced one here.

Answer 2

redston has many uses from torches to wire systems and triggered openig of doors to place down a wire simply carry some redstone dust look at desired place and right click

Answer 3

With red stone you can make electronics basically