In order to get meaningful replies, you need to be a little more specific.
1. What is your role and function as cluster HR
2. Type of business, timing etc
3. What HR / admin functions are already available at the stores
4. What software tools are available
But in any case, if you are appointed to be the HR Head of a cluster of 40 stores, I am surprised they are appointing someone without knowledge or idea of how to manage it. Is it possible that your question is not communicated properly? What exactly do you want to know?
I hope you are not asking us to tell you how to do your job