Matrix: How do I locally assign a label to my panel directly from the panel using ECS 5.2.3

You can locally assign labels to your panel directly from your panel. 
The panel has to be allowed to make local key assignments by enabling a tick box in ECS  Cards and Ports Menu / Advanced Settings. 
Then create a "Sort  Group" . A "Sort Group" allows the system administrator to sub-divide all the ports groups, party-lines and control on the system into smaller functional groups like creating a "sort group" of all the studio 1 control room panels and presenter IFBs.  The sort groups can also be named to aid the operator when selecting the sub-group.
See attached for full details.