I have to manage multiple bank accounts so how i can create party bank accounts and upload party banks statements.
Bit more descriptive use case would always help you to get best answer, anyhow you can start with following…
There is import and export tool as well, which works well for bulk importing/exporting data.
If you want complete isolation in terms of one company accounts to another then same ERPNext instance can supports multi company right out of box, where each company will have its own Accounting module. ie. Chart of Accounts, Journals, Reports etc. with some shared aspects controllable using roles and permissions.