Sandeep,
You can refer this link to create internal table
http://wiki.sdn.sap.com/wiki/display/Snippets/How+to+create+a+dynamic+internal+table.
Now once your final internal table is ready, you can use index (fieldcatalog table) to refer each fields.
Based on that you can populate the table.
Let me know if this helps and revert if you need more info.
Thanks,
Sreekanth