Physical Education

If you're wanting to lift weights I recommend Starting Strength. If you are open to training bodyweight calisthenics in a strength-training style, I seriously recommend Convict Conditioning.

When I lifted weights I did Starting Strength. Absolutely solid program, even if the author/coach gives off a few "don't tread on me vibes". I did this in my early twenties for about 18 months before I switched to a bodyweight strength training system, since I found bodyweight stuff to be more fun and allowed me to train outdoors in parks and whatnot.

For the last 10 years I've basically been training using a slightly-tweaked Convict Conditioning system. Beyond the "grr convicts" gimmick in the book, the contents are top-notch and aren't pitching anything other than using bodyweight exercises as a serious strength and muscle building tool. It really kickstarted the progressive calisthenics movement in the 2010s. I've grown bigger and stronger for a decade using the exercises in this and the follow-up book (which is focused on some assistance exercises). The author outright says that their goal is to give you the building blocks to make up your own routines from the basic principles and does a good job of this, but also provides some sample routines to get you started.

In 2019 I threw in some mid-distance running (5ks and 10ks) as well, although I can't run atm due to life things and injury. Running interferes pretty noticeably with recovery, and can slow down your strength/hypertrophy gains compared to a pure strength or hypertrophy system and some people really don't like this. I found that I could still progress but it was a lot slower than before running, although I liked having the basis in cardio to complement the strength. I didn't lose much strength or muscle mass because I ate more to compensate and over time my recovery ability increased notably.