How to Hire External Subject Matter Experts

Hello, everyone. I'm trying to find some direction and best practices for hiring subject matter experts. My family business creates courses for a particular professional industry for licensing and continuing education purposes. Our content mainly comes from in-house as we are a family with three generations of background in this industry. However, we need to expand and work with other professionals in our industry to create more content. I'm just at a loss on how to go about the logistics... appropriate compensation, how intellectual property is handled (if they write the content but we build and deliver it), etc. Is there anyone who has experience in this who would be willing to talk with me and share your experience and advice?

Thank you!