Chances are if you have been noticed to have the necessary skills and possesses the right mental attitude to handle a specific task within a company, for sure promotion will always be yours.
In establishing a good company, you will undergo three stages. The forming, storming and the norming. This is actually the same when you get promoted.
During the forming stage, you will have to establish your self with the team you will be handling, letting your subordinates know who you are and knowing what their expectations are from you. This does not necessarily mean that you must live up to their expectations, you are human after all and is capable of mistakes and indecision, what you can do however is establish a common ground within and meet them halfway. The best possible solution is more often than not the right solution.
This is a very crucial stage because if you won't be able to establish your presence then the whole team will go down the drain.
What is important is that you keep your options open. Establish trust and respect with your subordinates and have enough courage within yourself to believe that you can accomplish your task. Always know that it takes courage to lead, so be brave in discovering the ups and downs of your new team. Do not be pessimistic about your abilities, after all you were promoted, this means therefore you got what it takes to lead.
Learn some tips and tricks from more tenured fellow employees who have the same position as you. This is very important since those people have survived as well which means they have the right skills and the right know how given the time they have spent with the position.
The path to professional growth, isn't always an easy one. You will encounter crooked and narrow roads as well as a lot of bumps but what's important is that you keep yourself headstrong and be aware of the new you.