To install ESET AV, you must have an existing licence.

Go to the website 

Select "Download" and then choose "Download for Business - I have a business licence"

Expand "Endpoint Security"

Underneath "ESET Endpoint Antivirus" click on Download.

If you have an existing AV product installed, then select "Installer with AV Remover - Windows 10, 8.1, 8, 7, Vista (64-bit)"

Click on "Download"

Once the file has downloaded, click on it to run it.

Remove any existing anti-virus (do not run multiple different Anti-Virus at the same time)

Use your ESET Username/Password when requested.