Gameplainer will search through YouTube for mentions of your game in video titles and descriptions.
Notifications will be raised in Discord with a brief outline of the video description and a direct link to the video on YouTube.
Setting up a YouTube monitor in Gameplainer is pretty straight forward, simply go to the Channels page, and push the + button next to YouTube.
Enter the search string you'd like monitored (use "quote marks" for phrases, such as "Space Pirate Trainer" for finding videos that contain the phrase "Space Pirate Trainer" and not just videos with "Space", "Pirate" and "Trainer" in the description.
There's a setting you can toggle after creating the monitor called Exact search string required. By default this is turned off, as the YouTube search API allows an "elastic" search, which means having "Bob's Burgers" as a search will also return Bobs Burgers (without the ' mark) - however perhaps it's important to you that only 100% correct searches are returned, so I added this checkbox.
Gameplainer searches the past 24 hours for newly added videos, however if it was posted longer than 24 hours ago (like as a scheduled post) it might not be returned to Discord as a notification.
I'm still hoping to resolve this in the future - though for now it's a known limitation of the service.