Welcome along.
Starting out your best bet would be to stick to the fire roads initially. You can get on one 100 yards up from the bikers hut. You will see trails off to the side you could try when the mood takes you. These are more often intermediate but 9 times out of ten you will finish on another fire road so should be able to build up a little route.
As far as Epping goes its prettty dry at the moment so a good time to see whats where. Once the rains come back lots of it turns into mud.
I have been a busy bee recently and started to add a few trails to trailforks, purely so I can see whats where and how to link them. I've mainly added trails I find enjoyable which means they mostly point downwards and probabbly not for starting out
But I have mapped a few fire roads and greens too, take a look:http://www.trailforks.com/region/epping-forest/
Hope that helps.