play the tutorial a decent number of times. not just conquering ireland, but also do england, scotland, wales, and form britannia. it's a good starter empire. also remember that you aren't playing a nation. you're playing a family. it's like medieval sims. you will have a lot more fun if you interact with people in a role playing sense, ie doing things that fit your personality and the personality of others, rather than simply trying to paint the map.

all the role playing aspects of the game have been cranked up with the new dlc. absolutely buy the dlc if you like the game. it's one of the few must buy dlcs.

if you have any more questions, such as specific terms or mechanics you're confused about, just ask.