Believe me, whatever you're doing, you can do more. And no, you won't overtrain; you'll just advance faster when you push your limits. I used to think squatting 405 pounds for 10 reps was great. Now I can do 405 for 25 reps and it's okay, but I know I'm going to get up to 35 reps. Don't be afraid of more weight and more sets; just push a little more each and every workout (even adding 2.5 pounds is great). The greatest athletes in the world have done things that everyone thinks are crazy, but these are the same people breaking world records. Trust me, you can always do more. Train hard, train harder!
Rest and recovery: Remember that muscles grow during downtime, not when you train, so allow a day or two between workouts when you first get started so that the muscles can recover and grow. You should show up at your workouts refreshed and at least as strong as the previous workout (there will be days when you aren't stronger, and you should expect them so don't get discouraged when it happens).
For every person who lifts weights these days, it seems there are two who have a podcast about it. There are more bodybuilding tips promising greater strength and muscle than ever before, and along with them a ton of confusion; one buffed-up Instagrammer says lifting heavy will get you swole, while a well-known fitness personality has claimed in recent years that two 30-minute workouts per week netted him 34 pounds of muscle in a month.