I) What's the Method?:
This method is also called "Reddit Stories Videos". The short explanation is that you will be running a YouTube channel where you will be uploading videos based on Reddit's subreddit Threads using Text-To-Speach to read the replies on that specific thread. However, in this thread, I will mostly be focusing on r/AskReddit as an example. There are 2 ways to make the videos, you can make them manually or using a program to auto-generate them for you. In this tutorial, I will mostly be going into the manual way. This is pretty much a basic guide to give an idea of the method, and you can do further research on it.

You probably saw a lot of them in your recommendations, and here's an example:

II) Tools & Requirement:
The method is pretty simple and doesn't require much other than basic tools which are the following:
Video editing software. (eg Adobe Premiere, Adobe After Effect, Movie Maker, Final Cut Pro, IMovie, etc...)
Photo editing software. (eg Photoshop, Paint, Lightshot, etc...)
Voice editing software. (eg Balabolka, WordTalk, Zabaware, etc...) Search for the voice called "Daniel" if you want to use that popular voice used in most videos.
Extras: Sound effects, white noise, short clip or an image for separators, Background images, etc... 

III) Step 1:
Assuming you already have the channel name, and everything set up except for the videos. 
You will first go to the subreddit you want to make a video about. In this case, r/AskReddit. it's https://www.reddit.com/r/AskReddit/
You will find a thread you want, an easy option would be sorting by TOP threads and choosing one. Let's take this thread as an example.
Now you want to start scrapping the screenshots. Start by taking a complete screenshot of the OP so it's like this
Now for the screenshots of replies. You don't want to have the full text shown from the start, you want it to show part by part as the voice is reading it. You can use 1 of 2 options:
Option 1: Hide the parts within the video editing software by adding a layer box over the parts and unhide them in the exact timestamps. 
Option 2: Taking the OG screenshot of the reply on Photoshop or Paint, and exporting multiple other screenshots, and hiding more of the text with each time you export.
The final result will be the following:
IV) Step 2:
Now that you got all the screenshots ready, you want to prepare the text-to-speech recordings.
You will copy the text of each post you took a screenshot of, and paste it in a text-to-speech voice editor and export the audio. Preferably each post a time for easier editing and moving parts around.


V) Step 3:
Now this isn't essential, but it makes the videos look good.
You want something to have separators between each post you show on the video. Easiest simple way would be using some "TV Static" clip and adding your logo over it. and have it as a 1-2 seconds clip between each post. 

VI) Step 4:
Now for the longer part. You will be loading your video editor and putting all the parts you did above together to create a full video.
Try to make the video look more customized by adding some background music on low volume.
You can also add some animated background to make it look even nicer so it's not just a plain static video.
If you're still confused, and want to watch video tutorial on how to make the video, check the following videos:
https://www.youtube.com/watch?v=yEvPZOYtoZg
https://www.youtube.com/watch?v=AW2gsSZxOIU

VII) Step 5:
Now that you finished editing the video and rendering it. You want to make a thumbnail for the video.
For that you will be using Photoshop preferably or any Photo editing software. 
You can simply copy any thumbnail style on YouTube as they pretty much the same. Background imagine + Text (usually the Reddit Thread Title) + Image on the side to attract the viewer.
If you're still having issues on how to make the Thumbnails, check the following video tutorial:
https://www.youtube.com/watch?v=tkouFW1tBBQ