There currently is no Beta available with Samsung. When there is one available, there will be a notification in the Samsung Members app with instructions on how to apply.
How do you register your phone for the android 10 beta mine is a galaxy 10+ tmobile version and its temporary unlocked
When beta is available it will be displayed in Samsung Members app.
I just had someone from Samsung chat tell me the beta is only available for the s8 s8+ and note 8. I don't think she's correct. Why would Samsung beta test on devices that old?