Here is a generic example instead.
Set a widget’s visible property to OSC{foo, false, true}. This will create a listener on osc address /widget_address/foo and return the default value false until a different value is received; the last argument (true) indicates the widget’s preArgs are to be passed to the listener and must be matched in order to change the listener’s value. It’s now possible to change the listener’s value by sending the appropriate osc message to open-stage-control or directly from the custom module:
receive('/widget_address/foo', 1)
Note: the osc listener’s syntax can be seen as a shorthand for a variable widgets whose value would be retrieved with the @{} syntax.
A few simple custom module examples can be found in the docs to get started. You’ll need to learn some Javascript to understand what you’re doing though.