Thanks for the answer, but where can I find the Groupo SC10?
You're trying to use something from github, every github project belongs to a user. The bold part in
https://github.com/groupsc10/RSQL/ is the user, you can contact directly in github through issues page.
The problem is how do I pass the object created with the RSQL_Crypto_JWT.pas example into TRSQLClient?
As for your inability to understand an undocumented, let alone it's an ALPHA quality project with high chance of API change (the author has warned you in the README.md), the answer is you don't. The JWT handling is part of the extended fphttpapp server in RSQL_Server_Application unit. You use that server, you get JWT protected routes to access the DBMS, details in RSQL_Server_Router unit.