Kristin just means when you start burying start very shallow- and she is absolutely correct. In lesson 3 you and Lola were already doing shallow/ obscured hides in mulch. Mulch being the key here. Now we want you to do it in the ground. There is a difference in how scent moves between the different mediums. Soil is much denser and doesn’t allow odor to move the same way. Start very shallow- less than 1″ if possible and then once that is easy, vary the depths. As you progress to deeper hides – I consider 2″ pretty deep at this point- you ideally need to let them ‘cook’ for a period of time- 5 minutes to an hour or more if you have the time. This too, along with weather conditions, will change how scent moves and how Lola reads it. Eventually you will hide real truffles at these depths for practice
Also dig “fake” holes so you can check to see if she is alerting on disturbed soil as opposed to odor.