Microsoft launched a new app in the Windows Store called Surface Hub. It is designed for Surface Pro 3 users and provides the ability to customize the pen stylus.
You can currently calibrate the pen pressure sensitivity and test it out within the app. You can also adjust the top button to open the desktop version of OneNote if you prefer it over the default modern OneNote application.
In order to work with the Surface Hub, you will need to grab the latest Windows Updates as a new driver was released that allows the stylus to interact with the app in this way.
Using the app, you can also provide feedback to Microsoft about the Surface Pro 3. The app launched with English, Spanish, Japanese, and French with more languages to come in the future. You can read more about the app from the Surface blog where the Surface Hub app was announced.