To start out do a few random missions (ignore kill missions) to make some credits and get used to the basic game mechanics (supercruise, jumping to systems and galaxy map).
Since you've only make 23k and you're just starting out now is the perfect time to die. I'd find a resource extraction site (in the rings of a planet) or a nav becaon and find wanted ships and kill them. If you die it does't matter too much at this stage. It will teach you how to fight and how to fly. If you're ever in doubt then run. Learning how and when to run is the most underrated skill in this game. It's pretty much impossible to die to hostile interdictions in the later game if you know how and when to run.
Trading is one of the best ways to make money (the best in the high end ships) but until you can afford to buy cargo and have a ship big enough to make a profit and to know how to run to stop you losing your cargo you're better off using your time in a sidewinder learning how to fight, run and die.
Dealing with death is another important skill to learn in the game. A lot of us had a head start from beta and gamma knowing our progress was going to be wiped out so we learned the skills necessary to survive when dying didn't matter. Now I can smash my anaconda in to a wall with a full hold of palladium and laugh about it where as if I had played from the start and hadn't learned valuable lessons about the insurance system I wouldn't have taken such mistakes as well