Once the dog learns that step, you can progress to the next. A good rule to follow is to change only one variable per lesson. Some of the variables in evidence search would be the type of article, the place the search is being done, the type of ground cover, wind speed and direction, distractions, etc. All the initial indication work is done with the same article until the dog is reliable in its indication, then the same article can be moved to different environments, or different articles used in the original environment, but never both factors changed at the same time. Fortunately, the dog learns very quickly after the initial teaching of the indication, so although many different training situations need to be presented to the dog, only two or three repetitions, if that, need to be done with each situation.
Motivational trainers train often but for very brief periods of time.
This method requires the use of food as the reward to teach and maintain the behavior. If you have a problem with using food and building food drive in a dog for training purposes, then you are a little behind the times because food is being used by many agencies to train tracking and detector dogs, not to mention its widespread use by Schutzhund and AKC competitors. If you can't use food, another reward might be substituted, but food works best. The dog being trained must also have food drive. You cannot free feed a dog and use this method unless you can find a treat that the dog really likes and will gobble up like he is starving.