I suggest you to follow a similar dynamic to what Gary Burton suggests in his Inroduction to Jazz Improvisation course:
It's not for complete beginners, but you can follow a similar methodology from the very start.
Get familiar with scales and chords. Start simple. Add new chords and scales as you progress.
Start without chord progressions. Practice improvising over one chord, let's say C major triad. The most basic scales you can play over it are C major and C Lydian.
C major = C D E F G A B
C Lydian = C D E F# G A B
Improvise using those notes over C major. You don't have to be too rigid, you can play other notes if you feel like it. Just use these as base so you get to know them and how they feel. If you feel like two modes is too much to start with, learn the major first, then the Lydian.
When you feel comfortable with the major triad and the major and Lydian modes, add new chord qualities and modes. What about C minor triad now? The minor and Dorian modes get well with minor quality, so improvise using C minor and C Dorian over it. Again, if you feel it's too much, practice the minor mode first, then the dorian.
C minor = C D Eb F G Ab Bb
C Dorian = C D Eb F G A Bb
And just like that you are ready for your first progression. Now that you know how to play over major and minor triads, you can mix them up and play over them. Make up progressions of minor and major triads and see what you can play over them.
Your very first goal should be to know the 7 modes derived from the major mode, and which quality they are friendly with. For triads, it goes like this:
Modes for major triads: major, Lydian, Mixolydian.
Modes for minor triads: minor, Dorian, Phrygian.
Mode for diminished triads: Locrian.
The modes, in relation with the major mode, are:
Lydian: 1 2 3 4# 5 6 7
Major: 1 2 3 4 5 6 7
Mixolydian: 1 2 3 4 5 6 7b
Dorian: 1 2 3b 4 5 6 7b
Minor: 1 2 3b 4 5 6b 7b
Phrygian: 1 2b 3b 4 5 6b 7b
Locrian: 1 2b 3b 4 5b 6b 7b
Notice how as you go down, only one grade changes, this is a useful order to memorize them easily. Not only that, they are also ordered in relation of their chord friends! The first 3 for major triads, the next 3 for minor triads, and the last one for diminished triads.
For completion and reference, here is C in those modes:
C Lydian: C D E F# G A B
C major: C D E F G A B
C Mixolydian: C D E F G A Bb
C Dorian: C D Eb F G A Bb
C minor: C D Eb F G Ab Bb
C Phrygian: C Db Eb F G Ab Bb
C Locrian: C Db Eb F Gb Ab Bb
Just add one modes to your repertoire at your own pace, as you feel comfortable.
You then want to learn how these modes interact with 7th chords, other scales (like pentatonic, blues, diminished scales, etc) and the modes derived from the melodic and harmonic minor, but that's beyond the scope of this question.