There are literally millions of YouTube videos on soldering. (Just now, my search for “soldering” on YouTube returned “about 1,000,000 results.”) Here are two that I’ve seen recently recommended by fellow hams.
The first one was recommended by Will, WI9LL on Twitter. You can’t go wrong with a KE0OG video.
Alan Fanning KM4ZWW says
A real problem for many people like me from the Heathkit era is surface mount soldering. Just watched a very useful video on how to do it with just an ordinary iron.
Take a look at:
https://www.youtube.com/watch?v=3NN7UGWYmBY