Hi,
Welcome to ask here!
The SYSVOL folder is created and shared by default when the DCs are set up.
We do not need to build the SYSOVL replication group manually.
If you mean that you want to want to build a DFS-R group to sync files (not SYSVOL folders), you need to create the replication groups manually.
Create a Replication Group
If i misunderstand you, feel free to let me know.