I realise one or two related questions have been asked but I haven't found a solution.

I would like to create a checkbox group from the (unique) values in records returned by a query (ie not all values in the table which would be returned using 'distinct'). I then want to use the checkboxes to filter the records. This would all be client-side (the results are displayed using App Connect Traversal).

I know I can select a checkbox group and assign dynamic attributes to a checkbox, but I don't know what binding I should select. Do I need to add a repeat, repeat children or data view etc.? I've tried various options without success.

A list of unique values might be sufficient, instead of checkboxes. I've experimented with Data Formatter Collections - eg Values, Unique and Group By - but haven't managed to produce a list of unique values with any of these. I can't find any documentation or examples of how to use Collections (but they look promising). Ideally, I would like the number of records in each group to be displayed too, eg:.
Category1 (4)
Category2 (10)
etc.
I expect Count under Collections might do this - but I don't know how.

I would be grateful for any suggestions.