You need a GUI such as Arena or Winboard first - you can download these also on Chess.com
stockfish 151 ...how to start?

ok i downloaded and install winboard. What after that ? how i can use stockfish ? it still in command file

any one plz ?
Download arena GUI and read the help files. Stockfish is just an engine, GUIs are like cars. you can't run engine files alone.

ankitthemaster, with WinBoard, click on ENGINE and then LOAD ENGINE and point to the stockfish exe file.
Also, you should download a more recent version of Stockfish. The latest version is 2.2.2, which is much stronger than version 1.5.1. Version 1.5.1 is at least two years old. (Version 1.7.1 is early 2010!)
How analyse games on stockfish ? i just downloaded stockfish from chess.com but when i click on stockfish file ..black command file appears ...how go head from here i have no idea. Plz help