This page gives a quick overview of the basic UDON workflow, to get you started with the main functionality. The rest of the manual thoroughly documents every feature and option available.
To turn a node group into a custom node, select your node group, and then navigate to the UDON tab in the node editor's Sidebar. There you will find the Cook Custom Node button at the bottom of the Node Kitchen. Clicking this button will convert your node group into a custom node.
Once you have cooked your custom node, it immediately becomes available in Blender's native Add node and Search node menus. By default, it appears under a
Custom Nodes category, but you can change it to any existing or custom category (in the Node Kitchen before cooking, or in the Node Pantry afterwards).
When you select an instance of your custom node, a Deconstruct Custom Node button appears in the Node Kitchen. Clicking this button turns your custom node instance back into a node group, enabling you to make any necessary changes, and finally recook the node.
Making a Custom Node UI
UDON enables you to easily create a custom UI for your nodes, to control properties of the nodes inside.
To do this, in your node editor, enter the node group that you want to turn into a custom node. Then simply RMB click on the node property that you want to add to your custom node UI, and select Expose to Custom Node.
Every property you expose appears within the Node Kitchen, where you can manage them, customise the UI, and edit various aspects of the properties. Once you cook the custom node, all these properties are added to the custom node UI.
You can also link multiple node properties inside your group to be controlled by a single custom property. To do this, RMB click on a node property in the node editor, and select the custom property you want to link it to from the Link to Existing Property submenu.
This should get you started with making your own custom nodes. If you run into any questions, simply consult the relevant section in this manual, as UDON is thoroughly documented here.
Once you are comfortable with the basic mechanism of cooking custom nodes in the Node Kitchen, be sure to look at the documentation for the Node Pantry, where you can make your custom nodes globally available across your Blender sessions.