The posts in redlab are organized as a line, there’s no concept of depth or of post hierarchy. However you can still classify your different posts and trick this system to create main pages. As you can see on the picture there’s a category menu, you can add categories, and class your post among them.
To trick the inline display system, you can class your “introduction” post among the categories, and then put links (buttons) to the bottom of this post to others posts that are uncategorized. By doing this, you create a chain of posts with only one that can be seen on the home page, and the other ones are invisibles and can only be accessed by clicking on the button.
Below the categories menu, there’s the tag menu. You can fill this section to have tags related to your post, and then you can find your post by clicking on the concerned tags on the home page.
Concerning the select layout, the structure of this website took “Default Layout”.
Don’t mind about the sidebars.
I advise you to put a featured image only on the post that is supposed to be seen on the main page of the category, the one which is categorized, because if you put a featured image on uncategorized posts they won’t be seen anyway.