A farm yard is not necessarily a good place to hunt. Because for starters, although it may be an old farm, nonetheless, it is a single family concern, as opposed to a place where mutliple people gathered, for community things, recreation, travel stops (like stage stops, camps, saloons, parks, etc...). So I usually never hunt farm yards, unless there was some sort of express other purpose there for money-changing-hands, or recreation, etc... Like if it doubled as the post stop for all the neighbors, or had some sort of community gatherings (like grange halls, 1-room school house purposes, churches, stage-stop, etc... all of which were sometimes cross-over uses of certain travel route farm house locations). But if it's just a run-of-the-mill farm (unless super wickedly old), I usually don't bother. Also remember, that unlike city homes, country homes, in the old days, didn't have curb-side trash service. So the people would burn and bury their trash. And unlike city yards, which are kept up, mowed, kept clean, etc... country yard homes were where they worked on tractors, pitched out the kitchen trash for the chicken to peck at, etc.... So a lot more junky, potentially, than a city/urban yard.
Thus as Jeff of Pa says: "location location location".
As for the chaotic sounds and spastic sputtering signals, TIDs that jump all over, and no "rhyme or reason", you can do as the others have suggested, and do test beds of known targets (be sure to pick clean ground, far away from any structure, so you can be sure you're not putting coins etc... down where the ground is riddled with targets underneath/around them). Also air test a variety of signals, at all different settings (high disc, low disc, high sens, low sens, disc., pinpoint, etc...) Every type coins, samples of junk like wadded foil of different sizes, tabs, screws, bolts, nails, tabs, jewelry, etc.....
But even then, nothing can compare to the things you can learn, by hunting with a good hunter. If there's a club in your area, or if you can somehow hook up with someone good (someone who routinely finds old coins, not just a sand-box hunter), try to hook up with them. Have them take you to a place, even if it's just for recent clad, wherever there's prolific amounts of it, so you can "trade off" flagged signals to cross-compare. After he's shown you signals he'd pass, verses signals he'd chase, and after you hear those in-the-ground comparisons, and see what's dug thereafter, THEN the "lights will go on", and your machine will start to make sense (or you'll know how to better set the controls to get clearer responses, etc....). The reason why going out with a good hunter is so indispensable, is because there is simply no way, in print, for anyone to train or help someone else, with detectors. The reason for this is: detecting is very sound-specific. And a "sound" can not be described in print.
I have gone out with many beginners, who are ready to throw their machine away, and ..... no matter how hard I tried in email exchanges to diagnose their problem, it wasn't till we went out together, that I saw some glaring error on their part, etc.... I too was in this same position when I first got an Explorer, for instance: It was just a chorus of meaningless fluty tooty tunes, and I hated it. Yet I couldn't argue with Exp. users results. Finally, I got to hook up with a fellow who was adept at digging deep silver from the parks with his. It only took about 3 flagged signals, to hear what he was trying to isolate, and BAM, the "lights went on". See how no amount of printed text instructions could have done that? Only pulling your hair out and digging 100's of targets, or getting some side-by-side with an experienced md'r, will help.
I had much the same start as you, but thought there must be more, and better, and there was, and I found it! 
It just takes time.
![:-\](https://www.treasurenet.com/smilies/undecided.gif "Undecided :-\")
it takes time to get used to the sounds coming from your machine, but don't give up, dig everything and after time, things will become a lot clearer Why dosent it find anything
-- first things first see the "numbers chart" in the rear of your book? --its there for a reason -- it well help in telling you what you have "found" -- if a good find the numbers should repeat on a steady basis -- stuff that is "junk" is normally jumpy -- although "iron relics" can be jumpy some folks seek them out --if one is looking for old iron relic type items ( say you are in civil war campsite for exsample )-- digging in all metal mode and dig every signal might be advisible ----
