What is the knowing? It’s not the phenomena, not the mood, not the mind. It’s a basic openness that helps one get less impacted by the pleasant and unpleasant. Recognize the aggregates and how they are activated, then stay with the knowing where is no establishment, no activation. This knowing makes way for discernment to arise.
Samadhi is generally translated as 'concentration' but it is based on one-pointedness of purpose, rather than on focusing on a point in the body. As a factor of the Path, concentration represents the gathering of uplifting qualities and the removal of hindrances that block wisdom.