I want to import a Demo Theme as I want to update and re-do my current site. But before I touch it, I would like to know what happens to the current pages/content. I really want to avoid that the whole website is screwed up and would prefer to work on the new theme in the background and go life once once the new pages are ready and then simply delete the old content.
How can I do that?
The only content I would like to take over 1-to-1 are my blog posts.
Any suggestions/instructions are much appreciated.