(Version 13) How to reduce battle music volume?

Well, as the title implies, I want to reduce the volume of battle music in general (both against trainers and wild pokemon). However, I have absolutely zero scripting knowledge and am admittedly kind of afraid to tinker around with the scripts myself. However, due to the fact that I'm using additional scripts which don't work with versions newer than Pokemon Essentials V13 and are important for my game, I'd need the information for whether or not and how it works in V13 instead of the current version 15.1.

Sorry for possible mistakes - as English isn't my first language, I often make 'em - and thanks in advance for everyone trying to help.

Find this and add something like the red part (where 100 is the max volume, and 0 is mute)


That's for wild battles

Thank you very much! Now I just have to find the trainer counterpart. But knowing how to modify wild battles' music volume already is worth a lot.