To install ESET AV, you must have an existing licence.
Go to the website https://www.eset.com/uk/
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.