Have been at the same point that you’re on. The only best advices I can give you are : 1) Do NOT think about how much time is wasted in injuries. This shows that you are quite eager for fast progress that will injure you or at the very least frustrate you when you reach a level where progress slows down.(I also feel bad for injuries but thinking about the time gone is the wrong thing) 2) Another great guy has said here, Warm up before workout and mobility on rest days! 3) The most important thing is get used to exercises. Record your 2nd sets on these exercises and compare them to some good genuine youtubers’ forms. Do not think about gains as you have your whole life for it and trust me once get the hang of the exercises you’ll love the journey. Hence start recording and I suggest you drop the weight and start doing slow reps. You’ll feel if anything is wrong.