I’ll cover a few details Do Little didn’t clarify.
CCP makes a copy of the player database, including your skills, your wallet, your ships and other items you own, then copies all of that information onto the test server. The catch is that CCP does not do this data copy (mirror) on a fixed schedule. CCP only performs a mirror onto the test server when they think they need to, according to their game update and testing schedule. They normally announce when they are doing these mirrors here on the test server forum, but only CCP know when the next mirror will be done, there is no fixed schedule for it.
One detail to be aware of is that each time CCP does a new mirror onto the test server, your character data on the test server is reset back to whatever it is on the live server. Several times I have been testing a specific ship on the test server that I did not own on the live server. A mirror happens and I no longer have that ship any more on the test server because I did not own it on the live server. Save your fits for ships. Saved fits for ships do not appear to get blown away by a mirror.
It’s the same with skills, if I train skills on the test server that I have not trained on the live server, the next time a mirror is done by CCP, I have lost that training on the test server and have to retrain the lost skills again. Your training queue for the live server is ONLY for the live server. If you want to train skills on the test server, you must put them in your training queue on the test server.
If you are a new character, your character will not be on the test server until CCP does another mirror, and only CCP know when the next mirror will be done.