How do I publish a staging site live?
Go to Site Tools > WordPress > Staging > Manage Staging Copies. Click the Actions menu and choose a Full Deploy or Custom Deploy of the staging copy.
Differences between Full and Custom Deploy
Full Deploy -With a single click, you will overwrite your staging copy over your live site. In this process, both the files and the database of the live site will be replaced with the ones from your staging copy.
In case you don’t want to make a full deployment to live, you can use the Custom Deploy functionality instead.
Custom Deploy – It will compare all changes you’ve made to the files and database of your staging copy with the current state of your live site. This option is suitable in many cases.
For example, if your visitors have commented on some of your WordPress posts, you don’t want to overwrite your _comments table. This way of pushing your changes live gives you all the flexibility you need. You have control on every part of the copy that will be deployed to live.