If you don't want to import all content in order to make the theme to look like the demo you should follow the next steps:
A. Go to Appearance > Theme Options > make the necessary changes, activate your needed Custom Post Types.
B. Set the Home Page
1. Add a new page and from page attribute select the Home Page template.
2. Go to Appearance > Menu > add the page to menu
3. Go to Settings > Readings > Select a static page for front page > Select the home page > Click "Save Changes"
4. Go to Widgets and fulfil the home page widget areas with widgets.
C. Create a Custom Post Type page (for ex: Staff, Speaker, Gallery, etc)
1. Go to pages and add a new page for ex: Speaker.
2. From page attribute select the template page.
3. Add the page to menu. (Appearance > Menu)
4. Go to Speakers for ex: and add new speaker.
All Speakers will be displayed in the Speaker page.