Congrats ! you are just starting your career in HR !
Primarily get the budget approval from Management for expansion.
First of all please collect the requirement details Dept wise/grade wise. Arrive at the skill set required for the vacancies. Have their KRA in place.
Plan for interview process- written test /Technical round/HR round.
Then start sourcing through various modes.
Walk-in advertisement (if requirement is in bulk)
Post the requirement in social websites - Facebook/LinkedIn/Twitter etc.
HR & Labour relations Consultant
Having said these there shoud be forcast of requirement coming from various depts, its review by concerned authority, Planning to procurement and budgeting and the initiating the HR Process of recruiting, inducting, training and compensation managing.
The scope of expansion should be such that it always refers to and abided by the policies and where possible scope of exceptions be autorised to right authority.