Obligations of a overseas company - CIS, gross payment status

The overseas company is registered with the CIS as a subcontractor and has gross payment status. As a non-UK company, we do not submit Corporation Tax Return. I am asking for information about the obligations of a overseas company registered in the CIS and having Gross Payment Status. How CIS deductions should be made? How should a company pay tax and National Insurance at the end of the year? Thank you in advance