Let's take a scenario that we need to develop as dexterity script using a .net assembly/DLL program inside the Dexterity script itself. We have to create the assembly/DLL which we need to use or else use from .net framework. In Visual Studio we have to create a class library project. Provide Name as you want in your project. In my case, i have given the name as MyAssembly . Add a new class to the project. Make sure that the access modifier of that class is public . Also, d efine public properties you need to access from the Dexterity script. public class ExtraFields { public string Description { get;set; } public List <Field> FieldList = new List< Field > (); } public class Field { public string Id { get;set; } public string Value { get;set; } } Compile your project. In order to use this assembly program in your Dexterity script, you