You could try to understand the functions better by having them print output rather than using them in the tutorial. 

Try to guess what the output should be to determine if you are using it correctly and you understand it.

You could also try reading up on the built in functions themselves. Try to get a sound understanding of each one of them using the method described above.

When I was hacking at lua and trying to write my own functions doing this for built ins really helped me to be able to think in lua.

It is kind of like being in kindergarten and being given five syllable words on day 1. You need to understand the alphabet first.

Thanks for the post.

Don't give up.

Keep Steeming!