I updated the forum version
It says that the current update has a Hebrew language
But when I look at the definitions I see that there is only English
Where am I supposed to find the other languages?
You're looking the languages in wrong place.
Just change your WordPress to Hebrew and wpForo will load the Hebrew language from PO/MO files automatically. For the translation customization please read the doc: https://wpforo.com/docs/root/translation/how-to-translate/