I think you are really going about it the right way. Play around with the scripts that are available and modify them to what you want. You aren't really learning Lua, but using Lua to learn LE3's API.
What I would do if I were you is think about what you want to do (not in code just a general idea). Then set out to get it working using Lua and Leadwerks 3. LE3 is so new that getting all these detailed Lua examples will take a good amount of time. No sense in waiting for all those, just dive right in and if you have questions, look at the API doc to see if anything stands out that could solve the problem you are having and/or ask on the forum.
Sounds like you have the basic grasp of Lua now anyway.