Filtering a Kanban helps you sort a list by one field.....and then also by another.
For example:
Show me all my potential cast sorted into ratings…..but only show me the ones from NSW
Press the filter icon in the top right 
and make your selections, you can filter by card categories or multiple fields.
If you'd like to, you can save this filter by clicking the button with the three dots on the far right and select save Filter. You can give it a name and choose whether the whole team can use this filter or only you.
Please note: a Kanban will stay filtered by the latest filter you used.