@KARTHICKE16770090

As an entry point, I would suggest going through the Pega savable data page module. To add to that, here are a few pointers:

Data source: The data page should also be conditionally sourced - if a local record already exists, you can do a lookup with the key as a parameter. If not, you should use a data transform. A data page can be conditionally sourced with a when rule to achieve this. 

Data save: You can either use an activity or a robotic automation as the data save option. Most likely, you´re going to use an activity, in which the following needs to be done:

1. Copy the primary page (contents of the datapage) to a temporary page 
2. Loop over the page list
3. Save the iteration (I'm actually doubting if a commit is needed - if this is used in a flow synchronously, the flow will commit all transactions at the end) 
4. Remove the temporary page