
If you want strength and flexibility, try to look for exercises that have large ranges of motion and work in more than one plane of the body. Use weights that feel challenging, but controllable and let the weight help into the stretched positions and I can’t emphasize this enough, CONTROL THE WEIGHT don’t unengage the muscles for the exercise and have the weight drop.
For starting out use very light weights as your body gets used to the exercises and ranges of motion (otherwise you’re likely to hurt yourself), and after about 2ish months of finding what you like for different muscle groups, aim to increase weight in your sets by about 2.5lbs per week for smaller muscles, and 5lbs per week for larger muscles (like back or legs). If you feel you can increase weight faster than go for it as long as you can control the weight
Reason why you don’t need to start all that heavy is because your body is not used to having muscles structurally worked like weightlifting does so you’ll still make progress early on. That only lasts for so long though, typically a few months in most people, and you’ll need stronger stimulus to grow (aka heavier weight)