How do I write a great marketing plan to sell a book to my investors?

[RBLee]

My church has offered to invest in the publishing of my motivational book. It is such an honor! Yet, I want to give them a business plan that will present a marketing plan to show how I plan to get a return on that investment for the church. I've never written a marketing plan and need some good advice on how to do that.

If you've marketed a book and know how to do that I would greatly appreciate your advice! I need to have it expressed in a simple way that I can understand, but with as much detail as possible, please.

Ty in advance!