How do block chain confirmations work?

[Justinmoon]

For a time now, I've been trying to learn more about the technical side of bitcoin, and I've heard that I can do so here. I so made the decision to ask here in the hopes of discovering a better explanation for some of the things I don't understand.

I discovered that a blockchain system consists of numerous nodes dispersed over the globe, each of which keeps, confirms, and updates its own copy of the ledger upon the creation of a new block of transactions.
I don't seem to comprehend how more blocks increase transaction security. And How do blockchain confirmations work?