As someone who’s gone through the flight training process, I can answer a few of these.
The first thing you should do is look for flight schools in your area. These can be mom and pop flight schools or even large FBO’s or brand name schools that give flight instruction. I assume this is what you consider “recreational” training as opposed to going to an aviation school such as Embry Riddle. You also need to consider what kind of instruction you want to receive. You can choose to complete your license under part 61 or part 141. In short, part 61 is a lot more laid back and relaxed but has a higher number of hours in which you can receive your license, while part 141 is a lot stricter and regimented in the lessons that you complete, but the number of hours in which you are eligible for your license is less. I would suggest reaching out to the flight school that you are interested in and ask them what kind of instruction they offer.
For getting into flight training, I would simply suggest calling up the flight school you’re interested in, maybe taking a tour or discovery flight, and more often times than not, they’ll set you up with a CFI and you’ll be on your way. In the United States, you need to at least be 17 years of age to receive your PPL, (16 to solo) but you can begin training any time. Your instructor will have a lot more information on what you need to do to complete your license, but you can view the full requirements under 14 CFR 61.109 (just google this).
Your PPL will allow you fly not for hire and recreationally, but you need at least 1500 hours for an ATP license (which all airline pilots need to have). Many people do this by getting their instrument rating (lets you fly through clouds and under IFR), commercial certificate (les you fly for hire), and CFI (lets you instruct other students and build hours), but I would worry about finishing one thing at a time before even thinking about the next. You need to walk before you can run!
Best of luck to you and if you have any questions, I’d be more than happy to help.