In the description, you have mentioned only about VSE extension.
Did you even checkin the VSE software package to the ePO repository? Is VSE listed there?
If yes then I assume that you have already installed agent on the client machine.
From the ePO side, please create a deployment task (on one machine) to deploy VSE, schedule the task to 'Run Immediately'.
On the client machine, please open agent monitor window (CmdAgent.exe /s) and click on 'Collect and send props' and see if the task is getting initiated or not.
If not then something wrong with agent and you should try deploying agent again.
If task is getting initiated then I will suggest you to look at VSEInstall log file on the client machine.