create user LENA password '123' grant admin role;

CREATE ROLE BUH
SET SYSTEM PRIVILEGES TO CREATE_USER_TYPES;

CREATE USER LENA PASSWORD '123';

GRANT DEFAULT BUH TO USER LENA;

SET TERM ^;

EXECUTE BLOCK
AS
BEGIN
  EXECUTE STATEMENT 'CREATE ROLE USER_ADMIN SET SYSTEM PRIVILEGES TO USER_MANAGEMENT'
  ON EXTERNAL 'security.db'
  WITH AUTONOMOUS TRANSACTION;

  EXECUTE STATEMENT 'GRANT DEFAULT USER_ADMIN TO USER LENA'
  ON EXTERNAL 'security.db'
  WITH AUTONOMOUS TRANSACTION;
END^

SET TERM ^;

COMMIT;

isql
Use CONNECT or CREATE DATABASE to specify a database
SQL> connect 'inet://server:3054/test' USER LENA password '123';
Database: 'inet://server:3054/test', User: LENA
SQL> create user BOB password '123';
SQL> set list on;
SQL> select *
CON> from sec$users;

SEC$USER_NAME                   SYSDBA                                                                                                                                                                                                          
SEC$FIRST_NAME                  <null>
SEC$MIDDLE_NAME                 <null>
SEC$LAST_NAME                   <null>
SEC$ACTIVE                      <true>
SEC$ADMIN                       <true>
SEC$DESCRIPTION                 <null>
SEC$PLUGIN                      Srp                                                                                                                                                                                                             

                                                                                                                                                                                                          
SEC$USER_NAME                   LENA                                                                                                                                                                                                            
SEC$FIRST_NAME                  <null>
SEC$MIDDLE_NAME                 <null>
SEC$LAST_NAME                   <null>
SEC$ACTIVE                      <true>
SEC$ADMIN                       <false>
SEC$DESCRIPTION                 <null>
SEC$PLUGIN                      Srp                                                                                                                                                                                                             

SEC$USER_NAME                   BOB                                                                                                                                                                                                             
SEC$FIRST_NAME                  <null>
SEC$MIDDLE_NAME                 <null>
SEC$LAST_NAME                   <null>
SEC$ACTIVE                      <true>
SEC$ADMIN                       <false>
SEC$DESCRIPTION                 <null>
SEC$PLUGIN                      Srp                                                                                                                                                                                                             

SQL>

create user LENA password '123' grant admin role;