To locate an individual portrait or members of a group in your index, use the Filter dropdown option under the Index tab.
Pick a category on the first dropdown... in this case, we're looking for the category of Teacher:
Then select the group or name associated to the portrait(s) you want to see on the second dropdown.
In this case, we want to see everyone assigned to English's classroom.
The portrait thumbnails will update to only show those that match the selected filter.
Below, now you only see portraits associated with Teacher=English.
Note that you can search for an individual person by choosing the first or last name options.