A 4d, also known as 3d, skin is a model imported into bedrock minecraft that bypasses minecrafts geometry restrictions when using the right tools. One of these tools is horion.
there are quite a few steps, and they will take a while to do.
1. Download [Blender](https://www.blender.org/download/) or [BlockBench](https://www.blockbench.net/downloads), these are modeling softwares, one of which is made for Minecraft
2. Install the application of your choosing and begin modeling your character, you can find tutorials on youtube by searching ["blender tutorial"](https://www.youtube.com/results?search_query=blender+tutorial) or ["blockbench tutorial"](https://www.youtube.com/results?search_query=blockbench+tutorial)
3. When done, download your model and texture and upload to [Mr Arms Skin Studio](https://mrarm.io/skinstudio/) and export the file
4. Lastly, put it in Minecraft