Some administrators prefer manual installation to maintain complete control over all options. It is also sometimes required, as when the ePO - On-prem server is not connected to the Internet.
Download the extension software from the Trellix download site.
In ePO - On-prem, select Menu → Software → Extensions, then click Install Extension.
Browse to the extension .zip file and click OK.
The installation dialog box displays the file parameters to verify that you are installing the correct extension.
Click OK.
The extension is installed.