How can I preview a contribution page
Hi Paul and Welcome to CiviCRM StackExchange.

You can preview a contribution page like this:


In the Navigation click on "Contribution" --> "Manage Contribution Pages"
You will find a list of contribution pages and on the right side "Links" which has "Live contribution page" (creating actual payments) and "Test Drive" (creating test contributions BUT real contacts)


Click on the link you want to use. To see the page as a visitor would, open the link in a private window of the browser.