What helps a lot for apps with multiple config files:

• if you tell the user to “add code xy to the config file” : tell me which file. is it the main config file? the one of the reverse proxy etc.?
• provide a sensible example library of the config structure. For example: duting the implementation of an importer for beancount I was struggling with what goes where. The example structure was really, really helpful.
• also, if you have configurations which allow different options: TELL ME THE OPTIONS! If I get an error during startup, that for config.foo the value “bar” is not allowed, I need a list of options somehwere, so many hours lost to find out what I can write to config.foo