The Modes are seven different scale within the same key Each scale has the exact same notes but a different starting point. You already know two of them; the Major Scale (Ionian) and the Minor Scale (Aeolian). The first step in this lesson is to understand the Mode Formula.
The concept of Modes is very simple. The Major Scale is the Parent Scale (Parent = Ionian). The Ionian Mode starts with the first tone of the Parent Scale (C to C). Dorian starts wit the second tone of the Parents Scale (D to D), Phrygian starts with the third tone (E to E), and so on.