I shall refer to HR Policies of the company first. Hence, ensure the establishment of HR Policy for the organisation. Set out with various procedures and processes required to be implemented. Establish the line of authority and responsibilities as per the hierarchy in the HR Department and involvement of higher management in the making of directives, its issuance, control, and monitoring mechanism.
Having said these, there should be a forecast of requirements coming from various departments, its review by concerned authorities, planning for procurement and budgeting, and initiating the HR processes of recruiting, inducting, training, and managing compensation.
The scope of expansion should be such that it always refers to and abides by the policies, and where possible, the scope of exceptions should be authorized to the right authority.