Depending on the type of Beta, you can install the latest beta version.
Please refer to the guide that fits the situation below
1) One UI Beta
- Beta Home screen > Select Beta you joined > Software update menu
(or Phone Settings menu > Software update > Download & install)
2) Watch Beta
(or Wearable app > Watch Settings > Watch Software update > Download & install)
3) App Beta
- Beta Home screen > Select Beta you joined > Download at Galaxy Store menu