Prepare a secondary database for an Always On availability group requires two steps: 1. Restore a recent database backup of the primary database and subsequent log backups onto each server instance that hosts the secondary replica, using RESTORE WITH NORECOVERY 2. Join the restored database to the availability group. Reference: https://docs.microsoft.com/en-us/sql/database-engine/availability-groups/windows/manually-prepare- asecondary- database-for-an-availability-group-sql-server