I am a 42 yo male. I am about 6'3, 293 lbs (weight fluctuates between like 287-293) . I only workout on weekends. I usually walk on the treadmill at my gym for like 20 minutes and then lift weights for twenty minutes. I do upper body one day, lower the next. I work 2nd shift during the week so I am trying to figure out how to fit workouts into my routine during the week too. My gym is open 24/7 though.

Should I lookup a workout routine online and follow it to get results? I just do random exercises 3 sets of 10 each normally.

Or should I just focus more on cardio? Is 20 minutes walking not enough? Since i started back to lifting weights six months ago, I have gained weight but wondering if it is muscle. I really would like to get down to like 230 pounds.