Hi Shailesh,
Go through the BPC IFRS Starter kit section 7, Integration with ERP
https://websmp205.sap-ag.de/~sapidb/011000358700001096592013E/BPCNW10_IFRS_Config_SP5.pdf
Key thing to note here is : you will need to identify transaction types coming from ECC , you need know how to load closing balances and movements. If your ECC is on sFIN then you have another extractor given by sap : 0FI_ACDOCA_10.
I prefer to use 0FI_GL_10 as it gives me YTD balances and I don't need to calculate the YTD unlike 0FI_GL_14 etc. where you have periodic data coming which you will have to convert to YTD by code.
Again this will depend on you how much detail you need from ECC (as 0FI_GL_10 brings summary information)
Thanks,
Rakesh