Thank you! I just looking for getting programming skills alongside of gamedev. But gamedev is first for me. I did find info that Lua isn’t popular in commerce (outside of gamedev). However, I did find some popular Lua projects on GitHub and got an interest: “What can I do with Lua?”
Also, defold-kinematic-walker extention was written in Lua without C/C++. In couse of it, I decided that I need good understanding of Lua. Also I bought paper book from Lua developer (unfortunetly only 2006 year of publishing was available in my region).
In conclusion, I think, I was doing in incorrect order. Firstly I need to learn Defold manuals and practice at basic things.