Automatic select of checkbox

Hello everyone,
I would try to check the list a user's roles. I koGrid in a list of all roles of a user and if that user has the same roles present in the list I would try to have them selected.
The list of roles works, but how do we access the element to simulate selecting checkboxes.
You can help me.
Regards
Roby

The issue names KoGrid and asks how to select checkbox elements for roles already present in a user's role list, but it does not identify a file, test, or entry point. Start by locating KoGrid's checkbox-selection implementation and reproduce the role-list scenario; done should be defined as matching user roles appearing selected in the grid.

Written by the indexing model from the issue text.