Learn some simple basic jazz chords; Maj7, Maj9, 6, ,9, 13, min7, min9. Then learn some altered chords, min7b5, +7, 7b5, 7+9, 7b9. Learn a couple of simple standards using these chords. Like “Autumn Leaves”. This song is so great because it involves II-V-I in both major and minor. For instance: II-V-I in G Major is Am-D7-G. So using jazz chords, we could use Am9-D13-GMa9. II-V-I in Em minor is F#m-B7-Em. So try using: F#m7b5-B7b9-Em9. Start there. Get used to the “sound” of these chords. For most people they sound wrong or “out” at first, but in time they make sense to your ear and actually sound beautiful.
Don’t worry about soloing yet. Just play some standards using some of these extended chords.
Final note: LEARN THE MELODIES TO THESE SONGS. You can’t fully understand why the chords work unless you know the melody. Go on Youtube and find Autumn Leaves with a vocal; Sinatra, Ella Fitzgerald, etc. Listen to it over and over until you know the melody. Then search for an Autumn Leaves backing track. There are plenty to choose from. Play the chords along with the backing track. Then try to play the melody. This will give you a great start!
Soloing is another subject. I hope to tackle all of this in future videos.
Good luck!