So I got the game With the DLC and everything And now i want to mod it, but i hear i have to use the DLC merger.
Now It gives me 3 options to select, which option do i Choose? 1, 2 or 3
I will only use about 4 o 5 mods.

I've been using mods and modding myself for years and never even heard of this "DLC merger". If you just want to install a couple of mods, you don't need this "merger". Just download the mods you want to install, put them in your baldur.exe folder, and run the mods' setup files.

Usually, the option to choose is quite obvious when you know what you are doing...
can you copy/past the text in front of each choice ?

According to this, it should be 1, but both 2 and 3 should works (they are for a more general purpose...).