Hello, Natalino ,
At the moment, there are no guides and documentation yet. However, we are actively working on this.
As for the command syntax, then on this issue, you need to contact the manufacturer of the device or look for the syntax in the instructions for the device.
It is also important to understand that custom commands are not available for all types of devices. First of all, check your device and we can tell if custom commands are available for it.
By the way, some screenshots that might help: