v3.4.3 upgrade plus fusion-core plugin v1.3.3 update

Hi, I need help with something that sounds really simple. I’ve just upgraded my WordPress to 3.9 and have been told to upgrade my Avada to 3.4.3 and also update fusion call plug-in to v 1.3.3.
I don’t know where to start, i have login to my Themeforrest account, and can’t find a link to that upgrade. I’m also not sure how to go about doing these upgrades, any help would be appreciated.
Thanks

ThemeForest is not AVADA - AVADA is just one theme sold on TF among gazillions of other themes. You need to ask that question on the AVADA support forum, that you can find via the authors profile page.

To download the last version of an item you purchased - hover the mouse over your username on top-right and click on “downloads”. Here you will find a link to download the latest version.

You then need to activate another theme than Avada in your WP site (twentythirteen for example), then delete the avada theme completely, and upload the new version. Then, switch back to Avada when it’s installed. You may need to re-set the navigations menus and a few theme options, but your content will not be lost!

Good luck.