To start using Highlander, you'll need to set it up as a Custom Field within either Member Fields or Channel Entries.
Regardless of which installation route(s) you take, you'll be provided with the below configuration for your fields:
The actual HTML element to generate within your forms. You have 3 options
This is where you determine how and where uniqueness is decided. Depending on where Highlander is implemented you're provided with different options
The maximum character length to allow for the input field
Prevents writing to the input field, allowing data to be handled in other, programmatic, ways.