Hi Sameer,
Refer this thread.
How to write functional specs? | SCN
On your last reply, it looks like you need assistance on preparing the sample data. You need to explain,
Is the report can be generated in Standard or we need a custom report ?
What is your report all about ?
What are you trying to implement ?
What fields you want in selection screen ?
What are the fields required in the output ?
Tables and information's related to the report you want to built. Refer below for the entire table list
Plant Maintenance Tables | SCN
Regards
Terence