A headless CMS doesn't provide any presentation layer by default. But the editor's would want to be able to preview their content in a real website.
Lucent comes with 2 environments. One that delivers your live data and one for staging. By heading to Settings > Channel you will find the Demo URL and the Live URL fields. Fill them with your website root url.
Let's say that you have a Schema named "Blog posts". Head to this schema settings and you will find a field named Preview URL path. You can define the structure of your preview url by using some of the dynamic fields available {slug}, {id} and {locale}.
Let's say for example that the url for a blog post is "www.example.com/blog/post/hello-world". You should fill the input with blog/post/{slug}.
Now when you are inside the editing view of a document, you will have the option to preview it to a live url
