Read all the three introductory articles in the “Overview section” above.
In the “EMF Developer Guide” section of the Eclipse manuals read the following:
Scan the EMF homepage for additional information.
Look in detail at the ECORE specification and skim the specification of MOF / EMOF just to get a feeling how they are related or differ (how much more complex MOF is and how similar EMOF is to ECORE).
And obviously: Ask for advice before you get stuck and don't know how to continue!