Mechanics
Hero System uses point-based character creation. All abilities, from intelligence to run to fireballs, are bought with character points. Experience points are identical to character points, and are used identically. Characters who take disadvantages receive more character points than those that don't. The basic rule is that five points buys one die of effect.
There are essentially only two kinds of die rolls. "To Hit" or "Skill" type rolls, and "effect" type rolls. The first is done with 3d6, the lower the better, the second with a variable number of dice depending on the power level, the higher the better. For instance, to punch someone I would roll 3d6 to hit, and if I succeed I would roll 1d6 per 5 points of Strength for damage.
Hero System is function-based. A 1d sword, a 1d ax, a 1d fireball, a 1d bottle of acid have the same effect are handled the same, they are all Killing Attacks. If something about the attack makes a material difference, however, that attack has an Advantage, and the cost is proportionally increased. For instance, if the fireball is 40' wide, it has the Area Effect advantage, and costs double. If the acid burns through armor, it has the Armor Piercing advantage, and costs 50% more. If something reduces the effectiveness of an attack, it has a Limitation. If the fireball can only be cast once a day, it will cost 1/3 as much. But the others can be stolen, grabbed away, etc, which cuts their cost by ½.
Differences that make little difference are called Special Effects. To be gutted or hacked or burned to death makes little difference to most people. But special effects can come into play. If you're bracing against a charging ogre, only the sword will give you a damage bonus. If there's a door barred against you, you'll wish you had the ax. And the fireball will be real nice when you're attacked by a man-eating hay-bale.
Character Design
The best place to begin a Hero character is with origins and motivations. Because you begin the game at a heroic level, you have already done something. You may have followers, familiars, magic items, enemies. You may have children, lovers, mystic allies you can run to for advice. Where did all this come from?
Because this society is kinship based, it is a very good idea to give some thought to your family. Who are your parents, your siblings, your cousins? What have they done? What is expected of you, given all you've started with.
Motivations. Why do you do what you do? What do you dream of doing? Why don't you do it? What makes you willing to risk your life? When would you draw the line? How do you feel about killing people? What is it in your past that makes you do these things? Tell me more about your childhood. J
Because Hero System is thoroughly mathematically systematized, it is very hard to power game--play the odds and design the character that is most effective so you can triumph. Experience points are handed out on a scenario basis, not on a task or battle basis, so most of the time folks will advance as a fellowship or not. Only for occasional brilliance (either way) will a character be singled out. So do not fear to give your character real weaknesses and issues. That's what makes the game fun.
In this particular campaign, the choice of Tribe is central, and characters should give some thought to this early in the design process, so you can fit in (or not) with your kinfolk. If you want to be spurned by your people for being a reckless and headstrong warrior, and you choose to be Morhirrim, well, you really won't be very spurned for simple recklessness. And if you want to be a well-loved lord, well, you'll need to belong to a tribe that has lords.
Resources
To play a game in the Hero System, you must have a copy of the Hero System Rules, such as the edition pictured below left, available from Amazon.com
Not absolutely necessary, but quite helpful, is a copy of the Fantasy Hero campaign book, which applies the Hero System Rules to the Fantasy genre. The edition pictured below right is also available at Amazon.

