The first step to getting your persona out on the court is to physically create your Pro. This involves various settings to define your player's appearance, and their style. Both of these things are down to your personal desires really, and there's little right or wrong that you can do with this. The first key decision (if you don't care what color hair you get) really comes when you pick your player's positional attributes.
You can play whatever position you like, but there are a few archetypes that you will need to fit into. These include All-Round, Athletic and Defensive, while you can also choose to be a Shooting or 3-Point specialist as a Perimeter Player, or a Slashing or Rebounding forward.
TIP: If you are just staring out in the world of MyCareer, most people will tend towards coservatism, and choose All-Round. While this may seem like a sensible choice, it ends up hamstringing you, in reality, as your character will not excel in any particular area. On the other hand, choosing an archetype which gives you a speciality, or area of expertise, will give you a niche on the court that you can exploit and use to your advantage.
Your overall stats at this stage will be rooted solidly in the mid-60s - with 100 being the pinnacle, virtually unobtainable. You will still come across some players in the game with lower overall stats than this, so don't be too disheartened.
The best tactic for beginners is to aim to be as pickable as possible. What this means is to boost your chances of getting some playtime on the court by being a versatile player, one adept in multiple positions.
Add detail to create and craft your very own pro
By far the easiest way to get yourself some minutes early on is to create a player that focuses on the shooting guard/small forward role. You will need a player roughly between 6'5" and 6'8", and you want a bit of weight behind them so they can use their presence to influence the action at either end.
Note that physical attributes that you assign at the start are a definite help, but giving your player the Athetlic skill also has a great impact on the likes of jumping and hustle. The Athletic role is a great one to start with - things like shooting you can improve relatively easily, or cheaply at least.
Following all this difficult decision-making, you are then faced with your first game.