The most difficult part is likely figuring out how to use the ESO API. It's very poorly documented. To get some practice/understanding of the language first, you could use an online editor such as this:
https://repl.it/languages/lua
For Lua documentation:
https://www.lua.org/pil/contents.html
For the ESO-specific functions, this is the main overview:
https://wiki.esoui.com/API