Feedback Required Building X Factory Question

I have built a base that I liked in a gameplay expanded, etc, it's not underground and that's where the question lies, how do I export it to the factory to replicate it elsewhere or use in future saves?

 

You save it as a blueptrint by alt + O - "save as" Then you can send it to factory from blueprint list.

 

Do you meant extend the base, like join bits to it over time?