The Ilyushin IL-96 is a Russian four-engined long-haul wide-body airliner designed by Ilyushin in the former Soviet Union and manufactured by the Voronezh Aircraft Production Association in Voronezh, Russia.
I just port it from Arma 2, may be I can use it as air tanker(aerial refueling tanker IL-96-400TZ).
To install ILYUSHIN IL-96 you should use modfolders to keep it seperate from the official game content to prevent issues.
With Arma 3 you can use different ways to set up your modfolders to use custom content you have downloaded.
Please visit the Arma 3 Mod install instructions page
for more information about using custom mods and addons in Arma 3.