What Is A Chess Engine

Please forgive my ignorance on this topic. I did a site search on chess engine and didn't come up with a lot of useful information.

1.) What is a chess engine?
2.) What components are needed to use a chess engine and where do you get them?
3.) Is there more to a chess engine than playing a game of chess against a computer?
4.) Can you use a chess engine to step through games others have played?
5.) Is there any documentation on how to setup and use a chess engine?

And for the wisenheimers out there, yes, I just upgraded from candles 3.0 to electricity 1.0

1. It's a computer program (without a graphical user interface) that plays chess, it evaluates a position and outputs a suggestion.

2. Technically, you can use the engine by itself. Practically, you would also want a GUI, so that you can see the moves and pieces visually.

There're many commercial and free/open source options.

Some free engines: Stockfish (open source, GPL 3+), Komodo (commercial, 5.1MP and CCT are free), Houdini (commercial, 1.5a is free).

Some free GUIs: Scid vs PC (support thread here on chess.com), ChessX, Arena, Lucas Chess (mostly for playing, comes with various engines preconfigured).

Engines ratinglists: CCRL 40/40, IPON.

Some commercial bundles (GUI and the engine): From Chessbase (various engines bundled with some version of Fritz GUI). From ChessOK (Houdini engine bundled with Aquarium GUI).

3. You can also analyze the games. But remember, chess.com rules forbid the use of engines in ongoing games.

4. Yes.

5. GUI help files should provide the information on how to setup a new engine. Usually it will be an option "Add a new engine" or "Add a new UCI engine", something similar.