Weights. Can I do this alone?

This is a really good thread that lists some well-respected strength training programs others here have used, and the thread can be a good place to ask questions, if the posts don't answer all of the ones you have:

http://community.myfitnesspal.com/en/discussion/10332083/which-lifting-program-is-the-best-for-you/p1

I think to avoid injury it's helpful to have a personal trainer or at least someone, a friend, your son or whomever you feel comfortable with, who knows what they are doing to help with form, even if it's just initially. For example, watching a video on how to do a squat or plank will give a good idea on what to do and practice. But, if the posture is incorrect, it can cause injury, imbalances and so on, even if it's not immediately apparent or visible. Or you might end up exercising a different muscle then you had intended. As an example I had a trainer for a year, and then another trainer, and so I had good form. Fast forward five years later, I've been working out without a trainer. I just recently hired another one, and while my form is still good for the most part (habit from regular practice), certain aspects had to get corrected. My sister had the same experience. She had a trainer for a long time. Then went solo for many years at the gym. She was doing 20 push-ups a day. Then she hired a trainer again over the summer, who told her that her push-ups had lost form. When the form was corrected, she could only do 4 real push-ups because she wasn't engaging the right muscles anymore (it turned out that when she was doing 20 it's because she was cheating and relying on the incorrect posture/muscles/form). So having someone spot you or help you as you learn the exercises correctly, and then re-check once in a while really helps. This isn't to discourage you from videos etc. which are great. But a mirror and someone who is able to provide accurate feedback on details will make a big difference.

I'm in the same position. Don't know much about weight training and strength exercises. Cardio has always been my thing until now wanting to build more lean muscle mass. I am at a gym but am frugal so only taking the free first PT session. After tht I guess instructional videos, doing some research on different techniques, etc. Practice but start out easy don't wanna hurt yourself. Good luck! 😀

Definitely have someone at least watch your form for squats and deadlifts. Watching videos is helpful but the video can't watch you to make sure you're not rounding your back etc.

Another suggestion - start light , like maybe just a bare bar - spend some time on learning the technique before you use a weight that requires some effort

Strong lifts 5x5 has videos on all of the lifts they do. FitnessBlender.com will show you how to do all the exercises they do. Most on line exercise sites will show you the proper form for their exercises. Search for a plan, find a plan, try a plan and, if you like it, keep a plan. Iy you don't like it, try another.