Our simulations are designed so that at each step you learn and practice what you learn. Also, as you progress through the sim, you earn points by answering questions.
That's why you cannot skip a mission!
When you reload a simulation from the last checkpoint, it will bring you back at the beginning of the mission. If you are stuck in a simulation please check this article.
If a simulation has been completed, then you have the ability to replay a mission or the entire simulation from the beginning.
If you'd like to know more, do not hesitate to contact our support team: