Mess around with the game for a while, then ask people ingame what you should do next. After you reach level 18, look up wikis about "support job". Samurai job is locked until level 30 so just focus on learning the basics in the game as it'll be a while until you unlock it. Most important thing is to learn how battling works and try not to battle strong monsters until you are more experienced with fighting (unlike newer MMOs, dying still means a lot, especially for a new player).
This game is very cut scene and dialogue heavy, most of it is pretty good so give the story a chance. I know a lot of players skip it in order to level up fast.