After selecting your role, you are given the chance to select your character. For Hunters, simply choose whom you wish to play. If you have unlocked extra weapon skins, you can change that at this time. Skins are purely cosmetic; they provide no extra benefits. For Monsters, you must pick your Monster and then put three points into the four available abilities.
At this point, a Perk is selected to assist in your gameplay. To start out, only Level 3 Jump Height for Hunters and Level 3 Climb Speed for Monsters are available. As you level up, eight more Perks unlock for both sides. Once all nine are open, the second and third levels are unlocked for each.
Select a Perk that complements your play style, although you may occasionally want to select one that goes best with the mode or map you are playing next.