Socionics is quite a bit different then MBTI and I would say any understanding of the two topics becomes increasingly incompatible.
That said.
1. Start with Jung, socionics like MBTI is based off of Jung functions and there is a dominant function which is at the foundation of the individual.
2. Stick with functions. A ENFp is has extroverted intuition as a dominant function. This is the same for extroverted types between socionics and MBTI but different for introverted types. MBTI uses a different system for how it does its notation which is not compatible with socionics. Know what function is associated with each type and this should give you a clearer picture of how each type is constituted.
3. The key advance between Jung and Socionics is Socionics adoption of information processing and various aspects of information processing to the Jung functions. A human psyche process information of one type and produces another, the second function within the psyche is called the creative function and is the producing function which differentiates a ENFp from a ENTp. This divergence, the fork in the road so to speak produces the 16 types.
4. There is a lot to learn in socionics in comparison to MBTI and a great deal of in depth discussion of the various groups and emergent structures that form within the 16type categorizations.
http://www.the16types.info/vbulletin/content.php is a starting point and is a library of translations that has been done by the collaborators at this site.
Happy hunting!