For EZCA to connect to your ADCS CAs it is required for a domain joined machine to run the EZCA certificate agent web service. This web service receives authenticated requests from EZCA and then requests the certificate on behalf of EZCA. The fist step is setting up IIS in a Windows machine.
In a domain joined PC open an Administrator PowerShell window and run the following command:
Install-WindowsFeature -name Web-Server -IncludeManagementTools
Once IIS is installed, download web-deploy from the official Microsoft site and open the installer.