Create user from Kibana GUI with specifi role

Hi all, I want to create a user from the Kibana GUI who can read-only the indexes called " school ", " school_1 ", " school_2 “. I’ve created a user called “adam” with the backend role " kibanauser” so he can view the GUI.
How can I add the read-only role for a specific index?

Elasticsearch version: 7.7.1

Server OS version: CentOS 7

Kibana version: 7.7.1

You need to create a role and map it to the user.

Here is the first steps tutorial
And here you can find a list of available action groups (sets of permissions)