Adding a Role to Power BI Report Server

I need to create a role that will give our orginizational leaders browser access to all folders, dashboards, and reports.

The documentation provided by MS is actually for SSRS 2017, which is not Power BI Report Server even if it was built off of it from a backend perspective.

https://docs.microsoft.com/en-us/sql/reporting-services/security/role-definitions-create-delete-or-modify?view=sql-server-2017

1. In Object Explorer, expand a report server node.

2. Expand the Security folder.

3. If you're creating an item-level role definition, right-click Roles > New Role.

   Or, if you're creating a system-level role definition, right-click System Roles > New System Role.

If I open up the Security folder under the instance I have Server Roles.  Under the ReportServer database I have Database Roles, and Application Roles - this last one is empty.

Is someone able to provide some steps to properly add a browser role that will grant a specific AD group access to everything?

To follow up: Is there a way for this role to NOT BE REMOVED by content managers?