The connection to ePO is actually established by McAfee Agent For Linux - if you install the MFErt and MFEcma and the VSEL product - this does not install the components required for ePO communication.
You have to check the ePO agent for Linux into ePO and deploy to the linux machine(s) or get the Install.sh from the agent folder and run it locally on the linux system.
Latest versions of McAfee Agents are downloadable from McAfee download site with your grant number - and the documentation for your chosen version will cover installation for Linux Systems.
The guides are also available in KB - e.g https://support.mcafee.com In KnowledgeBase Tab enter :- PD24333
(This will provide the guide for MA 4.8 versions).
Oh... sorry didn't answer all questions
Direct link to MA 4.8 Guide :- https://kc.mcafee.com/corporate/index?page=content&id=PD24333
Commands for VSEL :- https://kc.mcafee.com/corporate/index?page=content&id=KB73316
Commands for Standalone CMA & full McAfee Agent :- https://kc.mcafee.com/corporate/index?page=content&id=KB81608