BundleRabbit does not know or advertise the fact you are seeking authors. You can use your blog, social media, industry contacts, etc., to spread the word.
This happens outside BundleRabbit and you should think through how you will be organizing this. Do you use email? Do you save the emails? What is your standard writeup to give to authors interested in your shared world?
This needs to be defined before authors contact you. The royalty split should be part of your contract with the authors. Keep in mind the royalty split can vary from book to book, but cannot change at BundleRabbit once the book is published. In other words, you cannot do a 60/40 split for the first six months and then 50/50 after that.
Do you read each book before it’s published or do you trust each author’s writing and editing, and just accept anything they want to publish in your world? Or are you somewhere between? Is this something you have in your contract with the author?
What type of branding are you doing on covers of books in your world? Are you providing the covers, an artist, or the author? Is there an approval process for covers?
Is each author responsible for formatting and creating the ebooks, or is this something you are doing? Will there be different epubs for each vendor?
Same questions about formatting and cover creation for the print version.
Regardless of who creates and formats the books, will there be a standard set of pages in the back matter? Links to other books in your world? This is a great place to provide information about your shared world.
Will you be creating the collaborative project at BundleRabbit.com, inviting the author to participate in the project, uploading the version for each sales channel, setting the meta data, and clicking the publish button? Or will this be the author’s responsibility?
Even if it’s the author’s responsibility to handle the publishing process at BundleRabbit, you may want the author to give you management access to the project. This gives you the ability to go in and tweak things if needed.