Here you can set your I/O List Settings for Terminal, Signal, and Label.
The Manage I/O's form is where you can add/edit/delete entries to your three lists that makeup an Input/Output in SI 2017: Terminal, Signal, and Label.
Here you can create a custom list of the names of Terminals, Signals, and Labels to be used when setting the Inputs/Outputs for Equipment in your Catalog and Start and End Terminals for Wires. These lists are available in the I/O Studio.
Use this dropdown to select which list you wish to modify.
The New button will create a new Terminal/Signal/Label and the Delete button will delete from your list.