Plugins for WordPress Multisite
If you are having trouble installing plugins on a WordPress multisite and getting a permission error notice, you have to contact your WordPress multsite site administrator / super admin to login to the network admin area to install and network activate the plugins for you.
The plugins have to be installed and update (in future) manually, the zip files for Revolution Slider (revslider.zip) and Fusion Core (fusion-core.zip) are available in Avada/framework/plugins folder. Grab them and send it to your site administrator to install those plugins for you from the network admin interface.
On WordPress multisite installations, only super admins have the access to install and activate plugins and there is no way by its design to give permission to users who don't have that role assigned.