There are a couple of tutorials that aim to make it easier to get started with mod. They are listed roughly in the order that it makes sense to read them in, since they'll often build upon each other.
There have also been some tutorials posted to the forums:
If you're new to Lua, one way to learn is to just have a look at the programs that come with the mod. For basic Lua information, do read the Lua Reference Manual. There are also tutorial sites about learning Lua, such as tutorialspoint. Finally, you may want to read more about how you can interact with components from within Lua and what built-in signals are generated.