To get quickly the same look of the theme as in the demo see here instructions to Import the Demo Content.
Adding Posts to Slider
To add a new post in the featured slider on homepage, edit the post you want to feature and check the Feature in Homepage Slider option.
Update or save your post.
Go to WPZOOM -> Theme Options and from Featured Section menu you can change additional options for the slider
Good to know
Don’t forget to upload a featured image for your featured posts. This will be used in slider.
The slider will work properly after adding at least 2 posts in it.
Setting up the Blog page
To create a page with all your posts, as in demo, navigate to WordPress Dashboard -> Pages -> Add New
Look for the Template box in the right side, and select Blog from the drop-down.
Publish or save your new page.
Widgets
To add widgets in the Sidebar, Homepage or Footer of this theme, you’d need to access Appearance -> Widgets menu, and drag widgets to your widgetized areas to activate them.
Widgets Structure in Demo
Load Default Widgets
From Theme Options you can load automatically default widgets, exactly as in theme demo. All you have to do is to navigate to Theme Options -> Import/Export -> Widgets and click the button Load default widget settings
FAQ
How do I change summary content (Excerpt) for a post?
On editing page of a post, look for a field called Excerpt. You can add here summaries for your posts each time you want to adjust manually the length of text which appears in Slider, Recent Articles, Post Archives or when you simply want to have a different text than the automatically picked excerpt.
How can I change the number of posts on homepage?
Go to Settings > Reading
Find Blog pages show at most option, and change the number of posts.