BTW, I have followed instructions at https://alienwp.com/documentation/oxygen-theme-documentation/:
1. Login to your WordPress admin panel and navigate to “Pages -> Add New”. Fill in a page title – ‘Home’ for example (doesn’t really matter) and then click the “Template” dropdown list. Select “Front Page” and then click the “Publish” button.
2. Go to “Settings -> Reading” and set the front page to display a static page – from the “Front Page” dropdown list select the title of the page we created in the previous step. In my case that was ‘Home’.
3. Start adding posts to your site from “Posts -> Add New”. Write title, text, images, video, etc. Choose category(-ies) and tags for the post. Then look at the bottom right panel and set a “Featured Image”. After all is done, there is just one final step – specific for this theme…
4. Just under the “Featured Image” box, there is another one – titled “Location”. If it’s not there, then you need to enable it by clicking the “Screen Options” button (upper right corner) and checking “Location” – then it would appear. This is where you choose where the post should be displayed on the home page.
5. Select “Featured” if you want the post to be displayed in the featured content area – as a slide. The next three posts with the wide thumbnails are the “Primary” area. And the remaining 12 posts – presented by their title and metadata only, form the “Secondary” area. So make your choice by clicking one of the radio button and then “Publish” the post. Note: You can remove a post from the home page later – by editing the post and selecting the last option “Do not display”. It will remove the post from the home page (but only from the home page!).
