In general, there are two scenarios.
- The most commonly used approach is to check out all the available Builder child themes and pick one which you like the best and customize it further to your needs, if desired. A list of all child themes is available here and here.
- If you want to re-do a already existing site or design say, in the form of a PSD, then BuilderChild-Default or BuilderChild-Foundation-Blank is recommended. BuilderChild-Default is designed to look just like the parent Builder theme.