Correct and safe use of equipment is essential in many situations. Traditional user manuals are not often available when working in the field and regular online instructions can easily be hacked. Our solution enables interactive user manuals and instructional video calls securely. All confidential material is encrypted and available on users' mobile phones - online and offline. Mumo is used by the leading heathcare device manufacturers in several university hospitals in Finland and other Nordic countries. Our solution is suitable for any use case where correct usage of any device or following a spesific procedure is critically important.