Reading fuel trims on obd scanner?

[gezhenry]

Bit of a general one here, I'm trying to read my short term (STFT) fuel trims on my obd reader but it gives 3 different values/readings, there's a STFT bank 1 (it says something like use this reading if it's the only one), a STFT bank 3 (which because it's only a 4 cylinder don't know what that represents) and then there's a Bank 1 O2 sensor 1 (bx-sy) reading, all 3 have different readouts and I've no idea which one s most representative.

Does anyone have any idea or experience at all?

Cheers