Section 195 of income tax act

As per this section any interest (not being interest referred to in section 194LB or section 194LC or section 194LD) or any other sum chargeable under the provisions of this Act (not being income chargeable under the head “Salaries”).

Please explain me the meaning of sum chargeable under the provisions of this act?

How to decide on which payment to Non-Resident we have to deduct TDS or not.