The Echelon Fit app has a tutorial video that demonstrates all of the following:
Seat Height: The top of the seat should line up with your hip bone. Turn the adjustment knob to the left, pull out and adjust. Then rotate the knob completely to the right to secure.
Adjust the seat to one of 4 heights based on your height. Your legs should not reach for the pedals (this is too high), nor should your knees feel cramped (this is too low). Adjust to your comfort and what feels best for you.
Seat Depth: (fore/aft) Find a comfortable distance where you have a slight bend in your elbows when holding the handlebars. As a guideline, the distance between your seat and handlebars should be roughly the distance between your elbows and tips of your fingers.
Handlebar Height: This is purely based on what feels comfortable and natural to you. A beginner would generally prefer the handlebars higher and a more experienced rider would prefer them lower.
SAFETY: ALWAYS MAKE SURE YOUR ADJUSTMENTS ARE SECURE BEFORE RIDING. THE POP PIN MUST BE ENGAGED IN A HOLE AND THE KNOB TURNED TO THE RIGHT TO TIGHTEN