You can install the latest Beta version based on the type of Beta test you have joined.
Follow the instructions below that correspond to your Beta type:
One UI Beta
Beta Program Home screen > Select Beta test that you joined > Software update menu (or Phone Settings menu > Software update > Download & install menu)
Watch Beta
Beta Program Home screen > Select Beta test that you joined > Software update menu (or Wearable app > Watch Settings > Watch Software update > Download & install menu)
App Beta
Beta Program Home screen > Select Beta test that you joined > Download at Galaxy Store menu