That's basically right (except that molecules don't vibrate "around the principal axis"). It is complicated by the fact that vibrational transitions may be accompanied by a change in the rotational state, and electronic transitions may be accompanied by a change in both the vibrational and rotational states ("rovibronic" transitions).
The appearance and interpretation of each kind of spectrum is different, as the energy level structure and selection rules differ for each kind. Thus, for example, I have done a lot of vibrational spectroscopy, much less electronic, and very little rotational; so I would be much more comfortable interpreting a vibrational spectrum than the other kinds.
You still haven't told us what it is you don't understand. Have you got any specific questions?