When you create a project in Kuika Boost, the project can be viewed and edited only by you. When you want to share the current state of your project with others you can "Publish" your project.
Publishing a project takes a snapshot of the project and makes this snapshot available in the project viewer in Kuika Boost. The Viewer allows you to look at pages of a project in detail but does not allow making changes. You can share a published project with others using their email addresses.
After you publish a project, you can keep on editing the project without changing the published snapshot. If you want your changes to be reflected in the published project, publish again. All your changes will be visible by people you already shared your project with.