Updating HC-Boards is pretty simple since usually, it does update itself.
Once an update is ready it will get downloaded automatically. After the download succeded you will get a notification. If you close HC-Boards now it will update itself silently in the background.
Within Streamlabs the update will be performed before starting Streamlabs itself.
Using the website you can simply download the installer again. It will upgrade your old version with the latest features.