My team is still working on the campaign page and/or application form. How can we do so without the page being public?

You can do so by keeping the page ‘unlisted’. That way, it will not yet appear in the overview of opportunities on the platform, yet it can be visited by anyone (your team) you provide with the direct URL. To unlist a page, click on “Edit page content” in your admin dashboard, navigate to the “Visibility” tab and select to unlist the page.