I tried looking on Roguard database, but there's only info about the equips, not from where I get it (either if it's a quest, monster drop, etc).
Someone can help me?
Side Question: Do I receive a bonus for completing a equipment set? Or there's no such a thing on RO2?
Side Question2: There are slots for Rings, necklaces, etc, but I didn't found any so far in-game. Where I can find some?
If you have the names of the equipment, I guess I can tell you where to get them. I don't know off the top of my head which ones are the best for a swordman... Though I guess it would be level 17 gear from Wolves Cave (any higher level gear is only for 2nd class), and Pandora Weapons from Pandora Boxes.
I'm not sure but i think accessories such as rings, necklaces, etc. can only be obtained through Pandora Boxes in the early stages, and from dungeons at level 50.
You need either Pandora Mallets (sold by Kafra Service NPCs) or Pandora Keys (kp shop) to open the boxes.
You'll recognize Equipment Sets because at the bottom of the description it will say something like "Bla bla bla Set (2): Effect 1 ... Blablabla Set (5): Effect 2", so it basically shows you how many pieces of that set you need to trigger the effect. I believe no such sets exist at early stages, and they most definitely can't be equipped without changing classes.