I will use barking do as an example, becouse thats what i know best
First things first: its good that the dog knows how to bark at command before beginning the training. When you do so, the dog will know right from the start what to do and that will reduce the possibility that the dog will leave te person in future. Why? usually, when dog comes to it's puberty, it will become alittle bit silly. Or, if the situation is new, exciting or something like that, its the same thing: in unexpected situation, dog easilly will create some "additional functions", like smell the ground, start suddenly playing with sticks, act like the person does not exist, or run from person tu person without signaling. In those cases the dog normally chooses an action that it has learned the best (for example when puberty-aged dog suddenly starts to leave persons and run from one to another, its most likely the case that the dog has been tought to seach before signal). If the signaling is very strong from the beginning, it reduces the possibility of false signals or even leaving the person.
So. The dog is tought how to bark. With food. It's a good motivation and easy to bring to the forest.
We dont use things like "sausagering", thats how its called in finland. People gather at a ring, sitting down, and the dog runs from person to another, taking treats. And what are we teaching really? to leave the person. So not that.
We begin with 1-4 persons in the forest, not far, but still so far away from each others that the dog does not see straight from one to another. The 'thing' is: handler goes to the forest with the dog like they would be going for a walk. Peacefully. Not interupting. Just walking. When the dog notices the person and comes closer, it's praised, treat is given when the dog arrives and then the person asks the dog to bark, teasing it a little with the treats. After every bark the dog gets rapidly a treat. After the handler arrives, praising the dog, the person gives a big treat to the dog (we use catfood! dogs love it!).
After that we continue the walk. And repeat this. It wont take more than 1-3 practices when the dog begins to search actively the persons. Then we start to think about the alignment. Upwind, downwind. But mostly it wont even be a matter, becouse the dog runs freely without interuption from the handler, and it's allowed to make its own choices and search for the smell on their own. Locationing becomes more reliable after many practices.
When the signaling is reliable and strong, we start the conditioning to different types of persons. We usually begin from sitting persons, then standing, then moving, acting, some might be picking berries, some having lunch at the forest, reading, smoking, sleeping, persons in a tent..
and always using the 'middletreats' after every bark when teaching something new, like walking person.
The big treat must be something the dog LOVES! something that makes the barking worth it. And there should be a lot of it.
The handler must always support the dog, encouraging the signaling dog, trusting it. So the dog will trust the handler that no harm will happen to the dog: its safe to bark, it's ok and safe to make decisions. THe dog should feel as the greatest, the best dog in the whole world after it finds.
We never use techniques that heats the dog up. THe dogs never see where the persons go, and we teach ourselves to trust our dogs from the beginning by not knowing where the persons go. So we will not teach the dog to always follow us, they should have the courage to decide to go other way it is the right way to go. We never show the dogs where to search, we are not the ones with the nose, we are the ones with the map.
So we dont point the goalpersons. We dont interrupt. We call the dog only if its reeaallly neccesary.
The goal is not to teach the dog to run straight forward in the direction we show. That's show-off and has almost no use in real situation. The goal is to teach the dog to find the smell and the source of it, on its own, and leading us to it, not so that we lead the dog to the person. We just haveto trust and support the dog.