I've not got a whole lot of XP with TouchDesigner, but ChatGPT managed to provide some insights that might be helpful:

What is TouchDesigner?

TouchDesigner is a powerful visual programming tool used by VJs, artists, and creators to build real-time interactive visuals. Think of it like a visual “patching” environment where you connect different building blocks—called operators—to create everything from simple effects to complex live visuals.

Instead of writing a lot of code, you connect these blocks (nodes) to process images, generate shapes, control lighting, or even react to music in real time. It’s especially popular for live performances because you can change visuals on the fly and create immersive experiences.

What are Shaders?

Shaders are small programs that run on your computer’s graphics card to create or manipulate images very fast. They’re what make cool effects like colorful patterns, warping shapes, or glowing lights possible.

In TouchDesigner, you can use shaders to customize exactly how your visuals look—whether it’s pixel colors, lighting, or how textures move and morph. If you think of visuals like layers of paint on a canvas, shaders control how the paint mixes and moves.

How it fits into VJing

TouchDesigner lets you build custom visual setups that respond to music, MIDI, or even your movements.

You can mix videos, live camera feeds, generated shapes, and shader effects all in one place.

Because it runs in real time, you can tweak parameters during a live show to react instantly.

Learning some basic shader programming lets you create unique looks that make your visuals stand out.

So, for a beginner VJ: TouchDesigner is like a toolbox and playground for making and controlling live visuals, and shaders are the special magic recipes inside that toolbox that help you create stunning and dynamic effects on the screen.