I surely can figure that you are a fresher also, its a construction company and not builders company.
You didn't mentioned what are the compliance they are expecting you to handle.
As far as joining formalities concern you should complete KYC, Qualification records, previous company's certificate etc.
The answer to your why is; Its called record keeping and maintaining the personnel files is one of your KRA as an HR. Don't worry you will learn the rest with time. Also we are here if you get stuck.
All the Best
27th March 2018 From India, Pune
Would you tell for which category of employee you need information? Whether the employee(Staff,Executive & Manager) of the company or others? The workman register/adult register, attendance register, Registers for EPF, Registers for ESI, Leave register, Wages register & OT registers. These registers are to be maintained as per the registration of establishments(factory, contractors, Shops and commercial establishment). You need to follw the rules of these where the proforma of the registers are give. By refering the rules you can able to know gradually.
28th March 2018 From India, Mumbai