Need help with arabic in InDesign!
I've got the font, but...
need help to understand how to get the text in right direction - from right to left.
(I've got the font)
InDesign CC (version 2015.4)
Windows 8.1 PRO (PC)
Correct. You don't need to uninstall your Western version. Arabic or Hebrew versions will install additional plugins into your version. InDesign keeps normally running in the UI language of you OS, if available, if not English is a fallback version, always possible.