Well, it's not hidden...you just have to do your homework. Presumably, you start with the installation manual, since you have to install the component before you can use it, and that tells you (along with the accessory manual for the pitot/AOA itself) how to do that, and how to calibrate it. The User's Guide then tells you what the pilot can expect to see and how to interpret/use it.
You, as the pilot, owner and perhaps builder of an experimental aircraft, are responsible for BOTH things...installing/calibrating/maintaining the systems, and how to use them in flight safely. That means you'll have to read both manuals, not just skim them or flip pages.
BTW, how did you expect an angle of attack indicator to function properly *without* any sort of calibration being done?