Imported HighendTheme istalled on top of default

Hello I bought the Highend theme and downloaded and installed no problem, I noticed the Import theme option which is what I did, but it installed over top of the other theme that was there, Default I guess, I am a newbie so was hoping just to have the imported theme working proper, so I can just change out the photos and text. how can I remove the underlying theme or Post? Thanks,
Tom