Project Online Creates Project Tasks instead of SharePoint Tasks

Paul_Mather  Thanks for the reply.

Do you mean using _api/ProjectServer/Projects/Add?

I have done that and can only pass few parameters in the body

{
    'parameters': {
      'Name':'Porject Name',
      'Start': '2019-09-26',
      'Description': 'Created from PowerShell using REST API'
    }
}

Still same thing, what am I missing?