If you are looking for the most authoritative "papers" or guides, these three are essential:
The mod must "listen" to variables like throttle , turbo , and brake to trigger specific audio samples. ETS2 Create sound mods
Since ETS2 uses FMOD, understanding the "Events," "Parameters" (like engine_rpm or exhaust_load ), and "Buses" within FMOD Studio is the actual science behind the mod. If you are looking for the most authoritative