The migration of data to an OES 2018 SP3 server running DSfW is similar to any other data migration to OES 2018 SP3:
You should use the OES migration tools.
When the source and destination servers are in the same eDirectory tree, only the data and trustee rights are migrated.
When the source and destination servers are in different eDirectory trees, the data and associated users are migrated.
For information on how to use the OES migration tools for migrating data, see the OES 2018 SP3: Migration Tool Administration Guide.