User's Guide - Trainers
Once you have some skill points, you will want to visit a trainer to learn and improve your skills and abilities.
Trainers can teach both skills and abilities. The general goal is to decide what "class" (profession) of character you'd like to have. Then seek out a trainer that will teach you that set of skills. You then train up your skills over time as you gain skill points, and train your abilities as they become available while you are training your skills.
Most settlements will have trainers. When you find a trainer, target him and type the "/trainer" command. You will get a list of skills and abilities that the trainer can teach, and the prices he charges. Type "/trainer train <SkillName>" or "/trainer train <AbilityName>" to learn a skill or ability.
