Magic item creation help!

[Dante Doom]

Hello!
I hope you guys can help me!

I couldn't find what are the prerequisites to make a +1, +2... Weapon.

Example: I have a long sword, to make it magical I need to pay for the masterwork. Then I have a masterwork long sword.
Now I need to make it a +1 weapon, what feats should I have, what spell I need, what is the caster level, should I roll a spellcraft?
And if I want to upgrade it to a +2 weapon?

PS sorry for my bad English...

[master_marshmallow]

Creating a magic weapon (+1) does not require any specific spell. To create a +1 longsword, you must have a masterwork longsword, and the Craft Magic Arms and Armor feat.

Creating weapons of higher enhancement bonuses only requires that you increase your Caster Level. Your caster Level must be 3x the enhancement bonus on the weapon in order to create that weapon.

At the end of the crafting, you must make a Spellcraft Check with a DC = 5+the CL of the item.

So you need Craft Magic Arms and Armor, a masterwork longsword, and ranks in spellcraft.

[Lifat]

You can forgo the Caster Level requirement. But doing so increases the DC of the spellcraft by 5. Failing the spellcraft check will cost you gold or result in a cursed item.

[LordSynos]

The above have the sum of it. Just posting the link to the relevant page of the PRD for your perusal.

Pathfinder PRD - Magic Item Creation

The "Creating Magic Weapons" section should cover it.

[Dante Doom]

Thanks guys!! It helped a lot!