A noble undertaking! I find them very useful, both on the road (esp. intersections) and in the woods (esp. when on a new-to-you singletrack).

I've never looked for any you tube, or other help, but I'm sure it's out there. I just kind of blundered my way through learning many years ago. You might want to start before Winter because initially a small hill or grade is helpful. Practice riding as slowly as possible, even momentarily stopping occasionally. Point your bike up the grade and slow down to the point of stopping and holding the bike going uphill with only your pedal pressure. That's the way I got it anyway.

A couple of notes: I learned on a fixed gear bike and it's still way easier for me on a fixie. On a freehub type bike you need to balance braking with your hands with stepping on the pedals. The fixed gear really just requires directional power input with either pedal.

Maybe I was a slow learner, but it took me a while....and it's also a skill I find requires routine polishing