Migration jobs represent a particular data movement process managed by Database Migration Service. They let you piece together the source and destination connection profiles, define settings specific to that particular migration process, monitor the progress, and safely finalize the data movement process.
Migration jobs progress differently depending on their type (continuous or one-time). Homogeneous Cloud SQL for SQL Server migrations only support the continuous migration type. To get a complete, step-by-step migration walkthrough for this migration scenario, see Cloud SQL for SQL Server migration guide.