Because the takeover command was specified with the -autofb option the resynchronization of the Primary from the new Primary and the failback are done automatically after the Primary becomes available again.

If you had not specified the -autofb option, then after the original Primary becomes available again, resynchronize the original Primary with the new Primary. After the resynchronization completes, failback the Primary role to the original Primary.

After the failback has completed, and the Primary role has been restored to the original Primary, you must restart replication to the Secondary. The data on the Primary and Secondary is at the same consistent point as was in the snapshot.