Do Self Employed or Sole Traders have to pay NIS or PAYE? If so, how do they go about doing so?

In Trinidad and Tobago, Self Employed or Sole Traders pays the following statutory deductions:

• Self Employed or Sole Traders do not pay N.I.S. Only unless they were in a corporate job, retired and maintained their N.I.S. payment immediately after leaving their job.
• P.A.Y.E. is only paid when your annual income goes over $72,000. Once it goes over, you must calculate the excess by 25%.  This is your income tax rate.