A friend recently asked me about getting into weight training. I've only been doing this stuff for a few years, so I'm far from being in a position to give expert advice. But I know what's worked for me, and I've put in a scary amount of time into researching all this stuff, so I thought I'd post my response to him, in case anyone else is interested.
The entire industry is a massive collection of completely contradictory information, and everyone who gives advice about this stuff online has an agenda, so the only way to get good info is to find common denominators of truth, and try various things to see how your body reacts and what works for you.
Another thing to note is that you have to seek out resources that you know are targeted toward natural weight lifters. Training as a natural and training enhanced are two completely different things, and the number of enhanced lifters out there is much higher than you would assume, so keep that in mind, both when getting advice, and when looking for inspiration.
The general idea is to follow slow, gradual cycles of building muscle (bulking), and shedding fat (cutting). Use an online calculator to find your maintenance calories. Start eating at around 500 calories below maintenance daily to shed some fat until you reach around 10% body fat. Aim for about 1 lb of weight loss per week. Once you're around 10% body fat, eat at maintenance for a few weeks, then switch to bulking at around 200 calories above maintenance daily, until you reach around 15% body fat. Aim to gain about 2 lbs of weight per month. When you reach 15% body fat, eat at maintenance for a short while and start another cut. It's hard to reliably measure body fat levels. Just use a mirror. Males start seeing ab definition at around 13%. Cut until you think you're too lean. Bulk until you're carrying enough fat that you're no longer comfortable with the way you look.
Aim for 1 gram of protein per lb of body weight per day.
I use MyFitnessPal to keep track of calories and protein intake.
So while there's some overlap, the two general camps are training for strength, and training for size/aesthetics (hypertrophy). You can spend years training for strength and not look like you spent any time in the gym. It's up to you where your priorities are. I'm in my 40s now, and I have no intention of competing in any strength contests, nor do I really want to risk getting injured by chasing heavier and heavier weight, so my approach to picking programs have always been for aesthetics. I just want to take my shirt off at the beach in the Summer without being embarrassed. There are programs that try to focus on one or the other. The basic difference is rep ranges. People who train for strength tend to stay in the lower-end; 2-6 reps per set. People who train for aesthetics tend to focus on higher-rep ranges: 8-15. I stay in the 8-15 range, and only occasionally dip below that. Going over 15 is generally considered to be in the endurance territory, and isn't seen as being very effective for building muscle.
Try to make a bit of progress every time you train - a tiny bit more weight, one additional rep, a little less rest between sets, etc. The gradual progress is what stimulates your body for growth. It's a very slow process for naturals (even slower for naturals in my age), and you might find that progress is essentially impossible during a cut. Indeed, you might find that you're losing strength during a cut. That's fine. The idea is to retain as much muscle as possible during a cut, by maintaining intensity in the gym and getting enough protein, and then build muscle while keeping fat gain as low as possible during a bulk.
Try to hit each body part 2-3 times a week.
I generally trust and believe everything this guy writes: https://www.aworkoutroutine.com , even though he prefers to remain anonymous.
When I started, I followed his beginner program: https://www.aworkoutroutine.com/the-beginner-weight-training-workout-routine .
After about a year, I switched to his intermediate program: https://www.aworkoutroutine.com/the-muscle-building-workout-routine .
I've had good results from both, and would recommend them without hesitation.
I've since switched to my own program, to better fit my schedule and my fatigue levels, but it's still based around the foundational principles of the above intermediate program.
I've read every article on that blog and it's all great stuff. I didn't buy any of his books, as everything is more than covered in the blog posts. The content on there is all well and sound, and I trust it.
Like I said, I tend to switch my workout from time to time to suit my schedule better and to adjust for fatigue (especially when I'm cutting for a long time and have very low energy levels). But if you're interested, my current workout is as follows:
Mondays and Thursdays - chest and back
1 heavy-weight flat bench chest exercise, 3-5 sets x 6-10 reps, typically a barbell or dumbbell bench press
1 heavy-weight vertical pull back exercise, typically 7 sets of pull-ups to failure.
1 medium-weight chest exercise, typically an incline dumbbell press, or a chest fly, 4-5 sets x 10-15 reps.
1 medium-weight horizontal pull back exercise, typically cable rows, 3-4 sets at 10-12 reps.
Tuesdays and Fridays - shoulders and arms
1 heavy or medium shoulder press, typically barbell shoulder press, 4-6 sets at 8-12 reps.
1 light set of lateral shoulder raises or rear delt work, 3-4 sets of 12-15 reps.
1 or 2 exercises for bicep isolation - ez-bar curls and/or cable curls, 4-5 sets each at 12-15 reps.
1 or 2 exercises for tricep isolation - tricep pushdowns and/or skull crushers, 4-5 sets at 12-15 reps.
Wednesdays - legs
Front squats (I hate back squats with a passion), bulgarian split squats, or walking lunges with weight, 3-4 sets at 8-12 reps.
Hyper-extensions (I don't do deadlifts, so this helps to compensate, and they feel *amazing* on my hamstrings).
Some notes about my current program:
I tend to also add a few sets of ab work every day.
I don't spend more than an hour at the gym.
I only do legs once a week. Yes I should be doing them twice a week. But I hate doing legs, I'm not entering any contests, they have zero input over my level of embarrassment in taking off my shirt at the beach, and they are fairly well developed as is, so I just do them once a week.
I do most of my sets to failure, and I do a lot of drop sets. Neither seems to be recommended by various online sources, but it works for me, and it feels good, and if that's what keeps me coming back to the gym consistently and retain high intensity, that's what I'm going with. I've had good results.
YouTube is dangerous because the "everybody has an agenda and many people are enhanced" thing, is multiplied ten-fold on here.
These guys seems to be OK and reliable (even if not very entertaining):
Jeremy Ethier: https://www.youtube.com/channel/UCERm5yFZ1SptUEU4wZ2vJvw
Sean Nalewanyj: https://www.youtube.com/channel/UCGXRegKvroyGv8HbN35AjKA
These guys are entertaining and inspirational, but I wouldn't follow them for advice (for various reasons):
Jeff Nippard: https://www.youtube.com/channel/UC68TLK0mAEzUyHx5x5k-S1Q
Jeff Cavaliere: https://www.youtube.com/channel/UCe0TLA0EsQbE-MjuHXevj2A
John Meadows: https://www.youtube.com/channel/UCmSEdfW3LpEKyLiCDWBDdVQ
Daniel Vadnal: https://www.youtube.com/channel/UC1CVzH-XVr3E-kTT6D8hhfg
On Reddit, I like https://www.reddit.com/r/Brogress , but, again, many are enhanced, and few of those admit it. Grain of salt.
Hope this helps!