First steps
In addition to the TwinCAT HMI project, add another Server Extension project to your solution:
In the following dialog you can choose which server version should be used for development:
If the project was compiled successfully, the extension can be loaded from the server. Open the context menu in the TwinCAT HMI project under Server/Extensions:
Activate the respective extension to be loaded from the Engineering Server:
The server tries to load the extension. The state of the loaded extension is symbolized in the project node Server/Extensions:
If a problem has occurred during loading, the error list or log from the server can help with error analysis.
After loading the extension, the extension symbols are available in the TwinCAT HMI Config window: