I wanted to create a simple custom map, but i didn't really understand how to do one.
I installed the modtools+ugx patch, then converted with launcher.exe.
To use the UGX script placer 2.0 i need to create the map with radiant first and then select it later?

And how do i add custom guns? I already have the required files, but i didn't understand if i can add ALL of the guns i want in the /raw folder, and then put in the map the ones i need, or if i must put ONLY the guns i will add to the map.

Use the script placer to create the base of your mod. It will create a .map file for you, which you can then edit, unless you already have a .map file that you selected to use when you used the script placer.

Adding custom guns involves quite the work, unless you can get someone to send you the files for it. I reccommend looking up tutorials on adding in weapons. There is a limit to how many guns you can have in your map, but you can remove stock WaW weapons to make room for custom ones, if so needed. 

Use the script placer to create the base of your mod. It will create a .map file for you, which you can then edit, unless you already have a .map file that you selected to use when you used the script placer.

Adding custom guns involves quite the work, unless you can get someone to send you the files for it. I reccommend looking up tutorials on adding in weapons. There is a limit to how many guns you can have in your map, but you can remove stock WaW weapons to make room for custom ones, if so needed. 

I've already got the files, but i mean how do i add them to the map? I'd like to keep SOME ugx guns, SOME stock weapons and some custom ones

I wanted to create a simple custom map, but i didn't really understand how to do one.
I installed the modtools+ugx patch, then converted with launcher.exe.
To use the UGX script placer 2.0 i need to create the map with radiant first and then select it later?

And how do i add custom guns? I already have the required files, but i didn't understand if i can add ALL of the guns i want in the /raw folder, and then put in the map the ones i need, or if i must put ONLY the guns i will add to the map.

I'd recommend watching some YouTube tutorials because they go through the entire process that you need to get started making a map. After you have the basics you should be good to go.

I'd recommend this tutorial series:

How To Make A Custom Zombies Map On Call Of Duty World At War On Pc: http://www.youtube.com/playlist?list=PLwlA8xZdjWAg0o9EGpticKPRm8LYZ6yk2

As MZslayer11 said check Corey Chanel(Gam3Vidz)
Other notorious youtubers are:
Zomb1e-Kllr: https://www.youtube.com/watch?v=QfFZspMSMTQ&list=PLc7t4ZxTyTwqpWQpxYwxIojFvnaAsQeup
AcademicProgramming: https://www.youtube.com/watch?v=TxDSly78HfA&list=PLVcaZ3TuoHV8gsSgGolFmrNT-KKE5ldN8