The software version of this update is N970U1UEU2ZSK3 and N975U1UEU2ZSK3 for the unlocked Galaxy Note 10 and Note 10+ respectively. The size of this update is more than 1900MB.
You can register for the beta program by opening the Samsung Members app, press the notification icon on top to go to the Notices section, and tapping the Registrations for One UI Beta Program notice.
Then tap the One UI Beta Program banner, scroll through the terms and conditions, then tap the Enroll button to register. After that go to the Settings > Software update > Download and install.