DetonationEMS is based off an open source project called Speeduino by Josh Stewart.
The Speeduino project is a flexible, fully featured Engine Management Systems (EMS aka ECU) based on the low cost and open source Arduino platform. It provides the hardware, firmware and software components that make up an engine management system, all provided under open licenses. Speeduino has matured into a product that meets the needs of the hobbyist and enthusiast community without driving prices to the levels of traditional aftermarket ECUs.
The Speeduino online manual can be found at: https://wiki.speeduino.com
DetonationEMS ECU's are based off the Speeduino Project. The official manual, forums, slack and documentation are the best source of information to understand how to use the ECU.
Official Speeduino Forum - https://speeduino.com/forum
Official Speeduino Slack - https://speeduino.com/home/community/slack