Player can use different kind of weapons:

If player want attack another player, he first select the target (see target button in the hud).
After select a target, player can select one of standard attack (button melee, button bow, button magic). The attack start automatically: player draw the weapon and follow the opponent. The attack continue until one player die (or opponent try fugue).
Player can switch from automatic attack to standard manual attack by click-ing left mouse button + arrows key. After fight player sheath weapon automatically.
In Manual attack he can use the default command /69 off (/69 on for draw weapon)

How combat meter calculate DAMAGE points

Players can see the calculation by activating Hit Log information from Hud Menu.

Menu button -> Other -> Hit Info
This procedure must be execute from player and opponent. During the fight, the results will be show in public chat.