I want to create a Lua script and to read a custom variable.

How can I access the variables in a lua script as I can use do with switches with "devicechanged" and with "otherdevices_svalues"?

Greetings
Erwin

Hello, I'm new here read a lot bout domoticz, but don't know how to start .... What do I need? - A reaspberry pi, what has to be installed on the rpi which operating system, ... where can I find it? - What else? Where can I find a schematical overview about the whole configuration? Where can I find ...