I am a new player and I must say I am quite confused learning the rules.

I have a question about character creation:When I create a character do I choose a weapon for free for my character to start with?If I choose a sword do I need a module to use it?What are the modules and where on my character sheet do I write them?

Thanks a lot!

This is stated in the rulebook, under the modules section I think. When a you invest points into your character's attack for the first time, you choose what weapon your character will have as base weapon. When you then purchase modules, then you add the new weapons to the first one as weapons without penalties.

I am not entirely certain the themed modules replace or not the base weapon, or are just added on. I would tend to think not, but I am not entirely sure. I would like confirmation on this.

The Attack and Block DPs you spend on your hero sheet already mean proficiency with either 1 weapon or unarmed. Hence if you decide your hero fights with katana, spending DPs on Attack and Block already gives you the katana module for free.

As a special "rule" I allow characters choosing a weapon and a shield as a base equipment, to have Attack proficiency with their primary weapon and defense proficiency with the Shield...also I allow to buy block with primary weapon and attack with shield for the same cost of buying a single weapon module (it's actually a half module for the primary and a half for the shield).

You get a single specific weapon. So you can't just know swords for free (that would require a weapon module: probably the similar weapon one) but you could choose long sword, short sword, or even katana.

If you then buy knight weapons or Ninja weapons, and it includes your free weapon, you don't nessisaraly get a new free weapon.