“To do Simran” is the physical act of sitting in a cross-legged position and meditating, uttering or chanting “Naam” – the name of God. The process brings calmness to the mind and allows one to concentrate on the “image” or “qualities” of God. The process is to allow one to “connect” to the Creator and “realise” His qualities. Sikhs prefer the name “Waheguru” to other names of God. Sometimes, the person doing simran will do this as part of a group or individually. Early morning is normally the preferred time although no one time period is considered more sacred than another.
Si – mar can also mean “to die over” such that you kill your ego in order to have union with the infinite reality.
A teaching that repeating Gods name will gain a person the humility to accept God’s Will (or Hukam) and become free of attachment. The person who wishes to gain and benefit from this human life and attain a higher spiritual state must according to the Sikh Gurus undergo the discipline of Naam Simran, remembrance, i.e. constant awareness of the Name.
The act of Simran (smarana) is on the one hand related to the act of “surati” (sruti) (concentration, focus) ie: listening to the teachings of Sri Guru Granth Sahib and on the other to the function of “smriti”, i.e. consciousness which means comprehension and retention of the teachings in one’s consciousness. via: Sikhiwiki