Facebook Ad – follow up

Hi Brooke,
Thank you for confirming that my stats from the FB ad is good. The cost per sign up keeps going down so now I’m at $0.67 per sign up 🙂
Now I want to ask you about the sale part.
I’m an artist and I sell paintings and online art courses.
My opt-in is an ebook that tells a personal story, with a bit of art history, and how to combine the two to have an idea for making your own painting, with step-by-step instructions.
Now I have a second book, like a sequel, that’s in the same format, but a different story, a different piece of art history and a different painting instruction. It’s also a full coloured book. A small book, but a full lesson nonetheless. I’ve priced the digital version at $2.99 on Amazon, but now I think I can sell that myself.
My question is what is the best way to sell it? In my autoresponder email 2 days after they opt in? Just any advice you can give would be great!
Thank you again, Brooke!