Dear Mohana.
I understand your concern, yes many people would have simliar concern when they move into managment level, but as subject matter expert as yourself, first as manager you should be clear of communication chanels because would understand how is your company or organisation is working, secondly see yourself with peers and what is your next step, in managment PDC ( continue learning and development) is what make you different from other managers, analysis the role of your organisation and your dept, see your department vision,mission what is the stratgies to meet them.
managers have to role in their department, continues preformaning according to companies KPI, nextly, continue improving the skills and your staff performance by making them movtivated and productive and this done with clear vision and understanding of your role.
lastly be member with international assoication, like Chartered Managers Institute ( site CMI) or be part of Management group in linked in, this international exlpore will inable you to use the managment techniques, like steakholders understanding, Organisation behaviors, the KPI's of staff performance and financial managment control's in departments.
I hope you some information and benefit it.
Regards
Iman- MCMI.-Oman