I believe you’re referring to this article: Getting the Most Out of Noise in UE4 By Ryan Brucks. This article describes how to bake volume textures in Unreal Engine (UE).
The method is quite straightforward. You create a blueprint that includes a Render Target and a Material. On the event Tick, the RenderTarget is cleared and then draws the Render Target from your material. When you place this in a level, it will already start drawing on your Render Target. You then create a static texture from your Render Target and from that a Volume Texture.
The material can be anything you want, but if you’re aiming to create a volume texture, you’ll need to fold your 3D texture using EncodeVolumeCoordinates (UE provides several examples that you can find using the Reference Viewer). For instance, for a 128x128x128 Volume Texture, you set your XY Frames to 16x8 and your Render Target Resolution to 2048x1024. If you want other sizes, they should adhere to the power of 2 rule. You use your EncodeVolumeCoordinates for your noise node of choice, but ensure to enable tiling and have its scale and Repeat Size identical (unless you’re doing unusual stuff with the coordinates). Your material has to be an AlphaComposite if you want to use the Alpha Channel, and your Alpha will get inverted, so you have to invert it back in the material.
For testing, I also recommend temporarily replacing the tiling coordinates with repeating World coordinates, as shown here, so you can see how your material looks and if it repeats properly.
On how to use your 3D noise texture to make cloudy meshes, there’s a bunch of guides out there. Here are some form my bookmarks, but they are old there’s probably better ones by now: Hugo Chenin, Sea of Thieves, Paul Neale.
I hope this helps. It may seem daunting at first, but it’s really not.