In the end it's pretty straightforward - and damn old invention
Audible sounds are differently vibrating airwaves. If you get to store and play back that vibration - voila - you have a record. Works with clay pots as well as seen on Mythbusters
OP have a look at that episode and you might understand the whole thing better.
Looking at the groove won't get you far - unless you are a DJ who has used vinyl a lot