Welcome to the forums, @david.lange! This post covers essentially what you asked:
Also, ‘sdb-admin dump’ can be used to export object definitions, users, groups, grants etc.
If your database is big, I’d recommend running sdb-admin dump and also taking a backup on the old cluster. Then restore the backup on the new cluster, and take the SQL script output by the dump utility and run just the part of it to recreate the users/groups/grants on the new cluster.