App does not have any free lessons or camera guidance. This app is simply an advertisement selling $29.00 manuals. By the way, every feature on your camera and how to use each in what situation is free in the manual and free for download, even as an official Nikon, Cannon app.
Plus, on most nikons, just hitting the question mark button on the camera while viewing every menu will teach you most of what you need to know.
Its all free already... Ill buy an inexpensive roll up water proof weather and snorkeling protector instead. That way Im confident that if it starts raining on a shoot (Portland, OR...) I can have it rolled up ready in my camera bag. The manual is absolutely step by step and free. Plus, Im confident there are plenty of free videos with hours of demos for every feature.
LuckyPDX about Camera Master - Master Your DSLR - For Nikon, Canon, Sony, LUMIX & GoPro