Udon

Udon is how to make code in VRChat worlds. It is a visual scripting language, which means it uses blocks and nodes rather than traditional lines of code.

UdonSharp

If you already know C# and would rather use it to write your Udon scripts using lines of code, you can use use UdonSharp[github.com]  to do so.

Note that UdonSharp behaviors are not MonoBehaviors. Not all methods in Unity's MonoBehaviors are exposed in Udon, which limits what you can code.

Getting

Started with Udon[ask.vrchat.com]

VRChat Udon TutorialsTutorial Videos Playlist

Many people view coding as a daunting black box. As a programmer myself, I can assure you that a basic understanding of it’s principles is not as complex as some portray it. The best advice I can offer you is:

Take it slow, don’t try to learn everything at once Don’t dabble or attempt to modify a piece of code until you know what it does Go in with a logical mindset

The last one is paramount. Think about the exact logical steps a computer would have to accomplish to achieve a desired result. Then putting it together will mostly be a process of translating that logic into computer code.

Oh, and the 2 most important tips:
READ THE CONSOLE!!!  and
WRITE COMMENTS!!!!!!!!!!!!!!!!!!!!!!!!!!

Unity runs on C#, so if you would like to start learning a programming language, C# would be a great place to start. As of writing Brackeys is creating a tutorial series on programming for Unity.  HOW TO PROGRAM in C# YT playlist

Basics

Data types:

Boolean - true or false Int - an integer Float - a decimal String - a collection of characters

Note that ints in C# are 32-bit, which means they have a limit of ~2.1 billion, positive or negative. Exceeding this limit will result in overflow, which will cause errors.

Alternatively you can use the community-developed UdonSharp. It will translate C# script into Udon Behavior. It is more reliable, and if you have basic coding experience I would recommend using it over Udon’s visual script.