CSGO minesweeper is a gambling game, which originated from a game called minesweeper that was attached to every computer with Windows. CSGO minesweeper is a simplified version of it, made for gambling. On CSGO mines you win by selecting fields that aren't mined. You can select the total number of mines in all fields, the more mines, the bigger your win will be after picking a field without a mine, but picking a higher number of mines is also riskier.
To play CSGO minesweeper (CSGO mines) you have to choose from the list gambling site that is offering this game. After that, you'll have to deposit your CSGO skins or real money to play. Some sites offer free credits for new players, which can be used to play on CSGO mines.