Weapon modules - you can read more about them along with the basics of starships here - are a subset of general ship modules. You acquire starship weapon modules either through drops from taking out NPC (non-player character) starships and players with the appropriate tradeskill will also be able to produce some of them.

Once you have modules installed, the next step to attacking anything with your starship is to turn on the weapon modules.

Activated modules may use some of your ship's shipsim cycles and/or your ship's power. You'll probably typically have your most important modules on most or all of the time.

Weapon modules can, broadly, be divided into two types: missile and cannon. You can load different kinds of missiles in your missile modules, and employ different kind of ammo batteries in your cannons. The major difference between the two is in when you can use them. Cannons (which could be anything from railguns to high-velocity autocannons) can be fired at something that is something around a 150° arc in front of you, whereas missiles (which are all homing missiles) may be fired from any direction, but only after you've achieved lock-on.

Damage Types

Depending on the type of missile or ammo battery you're using, there are four types of damage in starship combat. Further, each damage type has a % chance of having a non-damage effect on an enemy ship, with different effects for missiles vs cannons:

Kinetic - think railguns, for instance. Kinetic damage is more likely to damage/be absorbed by shields vs hulls than other types. Effects here include knocking the enemy ship onto a new heading.

Thermal - Damage from intense heat, which is more likely to affect the hull than shields. Effects include an increased chance of destroying active repairbots (see below).

EM - Electromagnetic energy is about equally strong against shields and the hull. Effects include losing target lock.

Gravitic - Gravity-based weapons are the most hull-oriented weapons. Effects include peeling speed off the vessel.

Typically, if a weapon leans hull or shield oriented, it means that it will be less effective against the opposite. So, using weapons that are mostly effective against the hull on shields would be less practical than using shield-specific weapons to take down someone's shield before opening up with hull-shredding weapons.

Weapon Ranges

All weapons have a particular range within which that weapon can be maximally effective. Outside of that range, each weapon has a different fall-off rate. Some might very quickly stop doing any damage outside of that range, some see their damage fall-off much more slowly.