It is a little complex.

I suggest you have a look at this project first : NodeMCU

Go to here to customize your own firmware.

Then you can see here to know how to burn firmware into D-duino.

I put my code on my github:

https://github.com/lspoplove/D-duino/blob/master/L...

Using Esplorer tool to write LUA is a good choice.

LUA is as simple as Arduino.

Please have a fun!