First of all, I`m not using the latest forge version as the EAQ said but I guess my problem is not really with the version.
Whenever I click in the forge installer the installer asks for how I want to open the .jar file (first image), At fisrt I thought it was a problem with java so I installed JRE (java runtime envirotment) and proceeded to start now the installer with the JRE file (second image).
I`m sorry if this isn`t that helpful but I don`t what to do, I already spent trying to figure out but it always ended the same way.
translations for the images:
1- "how would you like to open the .jar file
-.....
-.....
-.....
more apps"
2- "Java Installation not complete
It is not possible to install java
There are problems with the switches:
C:\\Users\mateu\Desktop\forge-1.8.9 -11.15.1.2318-1.8.9-installer.jar
Verify if the commands are valid and try again"