Step by Step - how does sending 1 bitcoin work?
You probably would find it helpful to peruse the technical articles on the Bitcoin Wiki.  Here are some starting points based on your questions.

https://en.bitcoin.it/wiki/Address

https://en.bitcoin.it/wiki/Transaction

https://en.bitcoin.it/wiki/Script

https://en.bitcoin.it/wiki/Network

https://en.bitcoin.it/wiki/Block

One concept you did not mention but which is crucial to understanding how it works at a low level is the fact that transactions are verified by running Scripts (see link above).