The idea that a scale starting on C is Ionian, D is Dorian, etc, is a cute, easy, music lesson, but it is of limited to no value for most people--the first question to ask, is, why am I being told about this? If you are going to be writing plainsong chants--OK--If you are studying Jazz, Good--Turkish, Arabic, Indian, Persian classical music, a logical place to begin--but if it doesn't lead you into a specific musical area, the idea of "modes" is simply confusing--

In practical terms, these Ionian, Dorian etc are really just names for seven of the hundreds of possible scales--you could use other names for them--and if you did, it would probably be less confusing.

To get the idea of what really modal music would be, think of the pipes, or the Applalachian dulcimer, or the Turkish Saz or any instruments that use a continuous drone--The idea is that the fundamental tonality doesn't shift--which is to say, the melodic line always plays against or leads to the same note--no chord changes, no key changes, and no   harmonies(other than the drone notes)--(keep in mind that this is a very general idea, just to help clarify a point, and not a cut in stone sort of rule)


And, just to make things more confusing, you can play modal music without using the Ionian, Dorian, etc--