I believe once the programme is ready it'll be shown in the Samsung Members App where a person can then register their interest to apply to be a Beta Tester @Moyah8
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.
As @BandOfBrothers said. Once it's out as public beta. It should show up in Samsung Members app to register. Right now, It's in pre-beta for developers. Pre-beta is now closed for applications.