Using the Software Catalog (ePO - On-prem version 5.10; Software Manager in ePO - On-prem versions 5.9 or earlier) is the most convenient method of installation. As an added benefit, you can also use it to upgrade and remove extensions.
Verify that the ePO - On-prem server name is listed under Trusted Sites in the Internet Explorer security settings.
In ePO - On-prem 5.10, select Menu → Software → Software Catalog.
In ePO - On-prem 5.9 or earlier, select Menu → Software → Software Manager.
In the left pane, expand the product categories and select Data Loss Prevention.
Select your Trellix DLP product extension you need to install.
In ePO - On-prem 5.9 or earlier, the install package and extension details are displayed in the lower pane.
For all available software, click Check In All. To install a specific extension, click Check In.
Select the checkbox to accept the agreement, then click Check In in ePO - On-prem 5.10. Click OK in ePO - On-prem 5.9 or earlier.
The extension is installed. Extensions that are checked in appear in the Checked In Software list. As new versions of the software are released, you can use the Update or Update All option to update the extensions.