Flow
Loading
There are 2 essential methods for defining your settings and parameters. OnPreLoad and OnPostLoad. As the names suggest, OnPreLoad happens before the module loads the user's data from disk and begins the loading process to get itself ready to be run. OnPostLoad happens after all this.
OnPreLoad is where you should define all the static things for the module. E.G, creating the settings, registering the parameters, and setting up any unchanging states, events, and variables for the ChatBox.
OnPostLoad is generally only used for setting up dynamic things for the module. E.G, creating states, events, and variables for the ChatBox that depend on settings. These must be created each time the module is loaded up, as after all this is complete the ChatBox then loads which first validates that all the data it needs is present, else it will refuse to load.
For a good example of this, you can check the Counter module's code. Since there is a setting to define the counters, OnPostLoad is used to create a Changed event and Value variable for each defined counter.
The recommened way is to setup settings and parameters in OnPreLoad and anything to do with the ChatBox in OnPostLoad to keep things clean.
Start
The OnModuleStart method is called whenever a user runs the modules. This can include the modules being automatically started. This is only called once on start so is the perfect place to do initial setup of anything your module may need to function, but which is dynamic at runtime. This method returns a Task<bool> to allow you to do an asynchronous start. Return false if your module has failed to start, true otherwise.
Stop
The OnModuleStop method is called when all modules are stopped due to VRChat closing or a user manually stopping the modules. This is only called once on stop so can be used to clear any OSC parameters on a user's avatar and reset local module settings (if they aren't already set to a default in Start). This method returns a Task to allow you to do an asychronous stop. This will block the user from starting the modules again until all the running modules have stopped meaning you don't have to worry about race conditions with OnModuleStart being called while your module is still stopping.
Update
To allow your module to have update methods, you define the [ModuleUpdate(ModuleUpdateMode mode, bool updateImmediately, double deltaMilliseconds)] attribute on any method you'd like to be called at a regular interval.
The ModuleUpdateMode you provide gives insight into how you'd like the method to update. A value of ChatBox updates just before the ChatBox evaluates. Custom lets you set a custom time using deltaMilliseconds.
The updateImmediately field will call the method once directly after OnModuleStart is called when set to true, otherwise it will wait deltaMilliseconds before the first call.
The deltaMilliseconds field defines how long the time is between the update method being called is.
It's recommended to set variable values in an update method marked with ChatBox.
Avatar Change
The OnAvatarChange method will be called whenever the user changes their avatar. This can be used to send out all your module parameters again to make sure the user's avatar has the correct parameter values.
Player Update
The OnPlayerUpdate method will be called whenever a built-in VRChat parameter changes. For example, if the user goes AFK and the AFK parameter changes this method will be called.