How to import themes to the application?

Excuse my English, but how or where can I get free or paid templates to export to the application and how I export everything since I don't know how to do it.

In English the opposite of export is import. Before proceeding further search the forums for "how to import external templates", only then should you seek to proceed further. This is standard practice in the computer industry. You will get the same answer with almost every other website development program.

Unlike as is the case with most other programs, there is a comprehensive set of tutorials accompanying this program. Please work your way through those before returning to ask other questions.