You need to add this guide to your Favorites, otherwise it will not show up when You try to select it in the Featured Showcase.
Profile -> Edit Profile -> Featured Showcase
Select "Favorite Guide" -> Select this guide -> Scroll down and press Save

Enjoy <3

(You need to be at least steam level 10 to add a showcase your profile. You also get another showcase every 10 steam levels. You can change these any time.)

Also check out my other Guides that as well are Spinning Audios and can be added to Your Steam profile.