You can assign a custom action to your S-Pen's Side Button from the Stylus tab in the Settings menu.

Important: This feature requires Concepts for Android version 2021.12 or later.

1. Open a drawing in Concepts.
2. Go to Settings > Stylus.
3. Under Side Button, choose your preferred action. You can set it to Select, Pan Canvas, Soft Mask, Hard Mask, Slice, or Nudge.

Bonus: With Concepts for Android 2021.10.2 or later, you can also set custom Air Actions for your S-Pen. Learn how to set them up here.