In the open consent settings, allow or refuse a service, by the name the dialog shows ("Matomo") or its machine name ("matomo"). Services are grouped by purpose and the groups start folded, so the step unfolds the group first. A required service cannot be refused. Save afterwards with "I save the consent settings".
Examples
When I allow the "Matomo" service in the consent settings
And I refuse the "Matomo" service in the consent settings
When we allow the "YouTube" service in the consent settings
And we refuse the "Google Analytics" service in the consent settings
When I allow the "matomo" service in the consent settings
Pattern
When(/^(I |we )*(allow|refuse) the "([^"]*)" service in the consent settings$/, …)
Part of @webship-js/drupal-cms-steps (github.com/webship/drupal-cms-steps), a step pack for Webship-js 2.0.x.