According to Osho, concentration means narrowing attention to one chosen object—breath, a mantra, a flame—and gently bringing the mind back each time it wanders, without strain. He adds that while concentration is simpler and useful, it is only a step; the flowering is choiceless awareness—effortless witnessing of whatever arises.
Pick one thing, softly keep attention there, and when your mind runs away, kindly bring it back and just watch.