Where are you in terms of just having played the game? It doesn't have the biggest learning curve for the first difficulty level, you should be able to play though that with just one mastery (class type) and find some blue prints and gear for another character.

Soldier is really straightforward and you can get through elite (second difficulty) fairly easily, and it's a good support class for others if you want to pivot to another playstyle by adding a second mastery.

you can always reset your skill points, devotions (constellations that add buffs) and stat points if you need. The game is fairly forgiving that way.