In melee combat, you can help a friend attack or defend by distracting or interfering with an opponent. If you are in a position to make a melee strike against an opponent you may roll an attack roll against a defense of 10. If you succeed you grant your advantage on their next attack. If they already have advantage from another source you give them a +2 to that attack as long as it occurs by the beginning of your next turn. You can do a similar a roll with defenses and skill checks. Using this requires 2 actions.
Charging is a special full-round action that allows you to move up to double your speed and attack during the action. However, it carries tight restrictions on how you can move.
Movement During a Charge
You must move before your attack, not after. You must move at least 10 feet and may move up to double your speed directly toward the designated opponent. You must have a clear path toward the opponent, and nothing can hinder your movement. If you don’t have line of sight to the opponent at the start of your turn, you can’t charge that opponent. You can’t take a 5-foot step in the same round as a charge.
Attacking on a Charge
After moving, you may make a single melee strike. You get a +2 bonus on attack and damage rolls, and take a -2 penalty to Defense until the start of your next turn.
A charging character gets a +2 bonus on Martial Skill checks made to bull rush an opponent.
Throw Splash Weapon
A splash weapon is a ranged weapon that breaks on impact, splashing or scattering its contents over its target and nearby creatures or objects. To attack with a splash weapon, make a ranged strike against the target using only your dexterity targeting an opponent's Dodge Defense.
You can instead target a specific grid intersection. Treat this as a ranged strike using only your dexterity against DC of 5. However, if you target a grid intersection, creatures in all adjacent squares are dealt only the splash damage, and the direct hit damage is not dealt to any creature. If you miss the target use a d8 to determine a random square next to the target in which the splash weapon lands.
If you wield a second weapon in your off hand, you can make one attack that does counts as an attack for purposes of the multiple attack penalty but ignores the penalty for the first attack you’ve made this turn.
Double weapons allow the same no penalty attack as regular two weapon fighting.
The same rules apply when you throw a weapon from each hand.
Shield Bash Attacks
Shields can be used for attacks, but if used as an attack you cannot use the raise shield reaction for the remainder of the round.