It really is impossible for us to give you proper advice without really knowing your innate tolerance. I have a fairly high tolerance, and half a pill (as suggested above) would do nothing. But my wife has no tolerance and half a pill would knock her out.
So really, best bet is to start low and go from there. IMO half a pill is too low, that's 2.5 mg of hydrocodone, which is already a weaker opiate. I'd normally tell a friend to try 15mg as a starter. But again, I don't know you or your tolerance.
And this is a "found" bottle, so I doubt you'll be having future experiences with this stuff.
The real advice I'll give you is don't go over the apap 24hour ceiling of 4 grams, and don't go over the 2grams in one dose ceiling.
Be safe.