I'm not sure what Tomo would advise, but he probably has a video (or multiples) for it!
In my opinion, you start by listening to jazz, and listening to it a lot! Purge the pop and rock from your playlists for a while. This will help you identify the form of the music, the rhythmic context you'll be playing in, the breaks, and bridges, and harmonic tools that span the progressions and setup the solos. The Real Book is often derided, but it IS a good starting point, if nothing more than to get a list of songs to listen to, and see how the form is put together.
After that, I'd just start with swing feel strumming the Jazz / Blues with R37 shell voicings. Lots of videos here on that, with some supplemental "distractions" added on top of the basic lessons to show what can be done, once you master the basics. Then learn all the 4-note Dominant chords in major and minor. That should get you going.
You'll start to hear things in the music you are listening to and soon you will be able to start to pick out what is happening by ear if you strum along. Very satisfying and rewarding to work on songs by ear.