How should I behave with my subordinates in office?

Instead of feeling superior to your subordinates, be involved in what they do. Set an example for them, your subordinates need to know that you are competent. This will make them trust you. Try not to force a relationship with your subordinates but get to know their desire and what drives them.

Teach them what they need to know in order to be better at work; do not be selfish to keep all the knowledge to yourself. Give them positive feedback when they improve on their efficiency.

Make firm decisions when necessary and take their suggestions into account. Rather than commanding a course of action, you should suggest it.
Hope this helps.

Be courteous and fair at all times. Remember that you are not better than someone else just because you hold seniority. You need to do your job well and facilitate others to do their jobs well also. Let your subordinates know that if they are in difficulty, they may come to you for guidance.

Learn to listen and consider whether any mistakes they make might have been true of you in earlier months or years. Lead by good practice at all times. Show that you are thorough and conscientious in your work and praise those who are working well or who have carried out something better than expected, or better than on a previous occasion. Never look down on people in lower grades than yourself.