In the section for restore the Primary there are multiple places where we refer to a secondary:
https://mms.mongodb.com/help-hosted/current/tutorial/restore-replica-set/#restore-the-snapshot-data-files-to-the-secondary
https://mms.mongodb.com/help-hosted/current/tutorial/restore-replica-set/#run-the-seedsecondary-sh-script-on-the-secondary
https://mms.mongodb.com/help-hosted/current/tutorial/restore-replica-set/#restart-the-secondary-as-part-of-the-replica-set

In the section for restoring a secondary we then refer to "primary" when we mean "secondary"
https://mms.mongodb.com/help-hosted/current/tutorial/restore-replica-set/#id3