key is a note and mode is a setting of its own, so set key E then set mode minor is E minor. Each keeps the other: after set mode minor, a later set key G is G minor. On a with, a block plays in another key.
Degrees and Roman numerals count on the key’s own scale, the mode’s. In D minor, iii is F and vi is Bb; in D dorian, vi is B; in D major, iii is F#. So the same line in another mode sounds in that mode: change set mode and the notes change with it. A b or # in front moves a degree or numeral a semitone off the scale, as minor’s raised seventh is #vii. The modes are major, minor, dorian, phrygian, lydian, mixolydian, locrian, harmonicMinor, melodicMinor and wholeTone. Each has one name: Ionian is major and Aeolian is minor. The mode also gives the sheet its key signature (D dorian has none, A mixolydian two sharps; harmonic and melodic minor take natural minor’s signature and write their raised notes as accidentals, and whole tone takes major’s) and how accidentals are spelt.
A lowercase numeral in a chart is the chord the scale has on that degree, so one chart goes up the scale and back down in every mode, and each mode makes its own chords. In D dorian they are Dm Em F G Am Bdim C: the iv, G, is major, where natural minor has Gm. In D minor the same chart plays Dm Edim F Gm Am Bb C, and in D major D Em F#m G A Bm C#dim. A quality after the numeral says the chord outright instead: iv is a major chord on the 4th degree whatever the mode, and a plain lowercase numeral takes the scale’s own fifth, so vii is diminished in major. The grooves have the same walk in each mode, lydian to wholeTone.
Harmonic minor is minor with a raised 7th, melodic minor (its ascending form) is minor with a raised 6th and 7th, and whole tone is six notes a whole step apart, so its degrees are i to vi and a vii is an error. The chart above in D harmonic minor plays Dm Edim Faug Gm A Bb C#dim, and in melodic minor Dm Em Faug G A Bdim C#dim.