Hi Noriko,
It is not mandatory to have a copy of Data recovered on secondary from Primary as a pre requisite before setting up System Replication
As long as you have the same version(or even higher version on secondary) and architecture(standalone, distributed with same set of HANA services on secondary) the System Replication can be started and HANA will do a FULL REPLICA first to make sure all the data is first replicated and then do a DELTA REPLICA for any changes that were made while the Full Replica was being synchronized
So please do not loose time recovering a copy of source system on destination system