(okay, so level 3 is not too bad. All we need to do are skill points and more hit points, we don't get a focus this level. We'll do HP first. Since it's level 3, you roll 3 d6.
If the new number is better than your existing HP, you get that, if its worse, you just get one more health than your old total. You will never have less HP than what you started with before leveling)