Modalities seem super obtuse and confusing but they can be understood most simply by picturing the scale or ladder from white key to white key on the piano using all white keys every time.
The two we know best are
C to C Ionian or Major Scale -Do Scale and
A to A Aeolian or Minor Scale - La Scale
Many EMM Students also play Greensleeves in the Dorian Mode in which it was originally written . It is often changed to Major to make it sound more modern.
D to D Dorian Scale Re scale.
Here are some examples of various Tonalities.
From Wikipedia :Modes are alternative tonalities (scales) that can be derived from the familiar major scale by starting on a different scale tone. Music that uses the traditional major scale can be said to be in the Ionian mode. For example, in the key of C, the Ionian scale would be C D E F G A B.
The other familiar mode is Aeolian. It can be derived by starting the Ionian (major) scale on the sixth scale tone. For example, A Aeolian would be A B C D E F G. This is the A natural minor scale.
The other modes can be derived similarly, by starting the major scale on the other tones. If we stick with only the white notes on the piano, we can derive seven different modes. These are:
As you can see, each mode denotes a unique set of intervals above the root tone. The result of this is that music written in each mode has a very distinct sound. Progressions that sound familiar in one mode may sound otherworldly in another mode.