Trying to understand Lightning Bitcoin

[LordD2]

I understand that it is meant to address the scaleability issues with Bitcoin, but not clear on how it functions I guess. I've read articles that this will result in, or has already resulted in a hard fork of the Bitcoin blockchain. Some articles I read say this occurred at 499,999 or something which occurred sometime in December. Was a new coin created at this time? If not, why not?