How to change Firebird user role?

Question

SQL

There is software that works with the Firebird database. There was a need to create users from the program and assign roles to them, I figured out how to create a user using a sql query like this:

create user john password 'fYe_3Ksw' firstname 'John' lastname 'Doe'

the user is being created, everything is fine, but here's how to assign it to the right group? Prompt when creating user type

create user mary password 'lamb_chop' firstname 'Mary' grant MyUserGroup role

is not executed, swears at the unknown MyUserGroup parameter, although a role with that name has been created. How right?
SQL queries taken from here

Answer 1

manual
Examples of Role Assignment:
Assigning the DIRECTOR and MANAGER roles to the user IVAN:
+ for Firebird there was a wonderful IBExpert IDE, the best of all for all subds. grants are placed in it in one click and, most importantly, for each admin action, you can see the corresponding SQL query