Dhian - refers to meditation, focusing on God, being attentive, etc.
Yes, every Sikh is suppose to practice meditation daily. Ideally we are suppose to do at least 2.5 hours of naam abhyiaas daily. God has given us 24 hours each day the most we can do is offer 10 percent of this day to him. The same way we offer ten percent of our earnings.
ਦਸ ਬਸਤੂ ਲੇ ਪਾਛੈ ਪਾਵੈ ॥ਏਕ ਬਸਤੁ ਕਾਰਨਿ ਬਿਖੋਟਿ ਗਵਾਵੈ ॥
God gives us 10 things ( human birth) but we waste this human birth by not even offering at least 10 percent to him. Many Gursikhs try to do most of their naam abhyiaas during Amrit Vela, because Amrit vela is the most effect time for meditation. When a person keeps a solid schedule of naam abhyiaas ( meditation on God) during Amrit vela then eventually Naam simran goes automatically through the day like a pendelum going back and forth.