You can defuse a bomb in Counter Strike, follow the simple steps below

Buy a defusal kit from the weapon store when the game starts.

When you reach the bomb just press E then a filling gauge should appear.

Hold the E button and wait till it fills out then the bomb should disappear.

That means the bomb is defused and counter terrorists will immediately win after that.

Note

Always be careful while defusing a bomb because at any time a terrorist would pop you out and kill you while you are defusing a bomb.