Hi Gourab,

       Here you can take real life example of purchase order. Purchase order will contain lots of information like customer,Line items,coupon code, addresses etc.

for example 

        Purchase order id = P-1

        Customer( Page): It will contain different type of data like Name,DOB,Address etc. Page is container for all these type of data. Customer record will be only one.

        Name: John

        DOB: 1/1/1900

        Address: Address(Current): 

                                       Street : xyz street.

                                        Postal Code: 001

                       Address(Permanent):                                        

                                     Street Name: abc street.

                                       Postal Code: 002

     Single customer record will contain many addresses you can check above current address, permanent address etc,

List of addresses is added using subscript like (Current) this record further divide using Street Name and Number

        Likewise  Purchase order  will contains list of Line items but that can be stored in form of Page List that is stored using index 

          for example,

                    Line item(1): 

                                 Product ID:1

                                   Name: abc                   

                    Line item(2): 

                                  Product ID:2

                                   Name: xyz

Page group and Page List is same Page group is just more readable and Pagelist is easy to access using index number.

Thanks.

Hope this helps