You can work on your own book with contributed recipes from family and friends. To do this, click on the "Contributors" button to bring up the invitation dialog.
Get a Contributor Link
You can share a link with people that will allow them to submit recipes to your recipe box. When a new contributor inputs a recipe, you'll get a notification, and you can approve (or deny) that contributor from submitting recipes to your recipe box.
Sending Invitations By Email
You can also send invitations directly from the cookbook designer. Just click on the "Contributor" menu option, and "Send Invitations" tab. Type in your email addresses for those that you'd like to invite. Remember to separate all of the email addresses with a comma (",").
Once you've entered your email addresses, you can modify the default message below that to personalize your message to your invitees.
When your message is done, click on Send Invitations. You'll get a verification message that your emails have been sent.
If you realize you want to invite more people afterwards, just repeat the process with your new invitees.
They'll get an email indicating with your message asking them to contribute recipes. After accepting the invitation, they'll join the cookbook project. They don't actually edit your book directly, but rather add recipes that are available for you to add into the book.
Here's the screen they will see.
Once they contribute recipes, you will see them available in your "Recipe Box". You will then be able to add them to your book.