I know this is just an ATMB question about starting a topic, but I’m going to jump in and suggest that if you want to learn about lock picking, check out LockPickingLawyer on youtube. While is more recent videos feature him picking locks, his older ones spend a lot more time showing what’s going on inside the lock itself. Including why one technique for picking it will work but another won’t.
Plus, he’s got an almost soothing/relaxing voice that makes it very easy to watch video after video.
Besides, a link to this channel is almost certainly one of the first ‘answers’ you’ll get.
PS, it should be noted that LPL is a ‘white hat’ guy. While his videos certainly show someone how to pick a lock, it’s not the aim of the channel. It’s very much more on the educational side, plus, when he exposes weaknesses and exploits, he attempts to communicate them to the company to get them to improve their products.
Also, you’re not going to watch a video and be able to pick locks. It’s still a skill that requires practice and sometimes specialty tools. In some of these cases, as he even demonstrates, it’s easier to just breach the lock itself (ie angle grinder, hammer, blow torch etc). Just like how you’re not going to watch a youtube video on how to play a guitar and be able to play anything other than ‘Three Blind Mice’ tonight when you get on stage.