Less than a week after you put your deposit down, they will contact you for configuration. Once you configure, you'll have a week to confirm the configuration you picked.
After that, when the car is being sourced for production, you will be assigned a VIN number and an approximate delivery timeframe.
At some point after that you will be contacted about final payment, pick up etc.
Finally, once your car is manufactured and QCed, it will be delivered.
Tesla is still figuring out and optimizing the last two steps, so it is all a bit of a mystery.