Hi Yamini,
I would suggest, you should start with making an organisational chart for your firm which will help you in understanding company's current hierarchy, gaps (positions need to be filled), grades and designations etc.
after that you can understand about the methods for leave and attendance and also about the leave policies.
Try to gather as much data as you can, try to understand functioning of your company, ask question to the person whom you are reporting to. gradually you will have a clear idea that what is your company all about.
Then you can switch on understanding the type of employees working like their qualification, designation, etc.
After a fair understanding try to create an employee handbook wherein you will put all the data regarding your company, the rules for employment, the leave policies, etc.
I hope this will help you..
good luck...
Regards,
Archana Kamble