If it has nothing that needs to be kept constantly powered then I'd suggest a switched live. That way it ain't flattening your battery when not in use (like alarms do).
Probably has a little cap inside for keeping short term memory without perm power.
Rest of it seems to point to what it's to be tapped into like your indicator circuits.
Are all your instruments US? else why fit it? unless it was a 'gizzit', in which case, why not.
I assume it came without instruction otherwise why ask the question. Do you know make / model of unit? in which case I'd be scouring Google for info / PDF installation guide.