I'm selling a course online. The co. is deducting taxes before my payouts. I have to pay royalties to outside hires. Do I pay them based on my pre-tax income, or post?

The course is on Teachable. I owe royalties to contractors for added work to the course. Do I pay them the royalty % based on my pre-tax income, or post-tax income? If it's from my post-tax income, do they still owe taxes?