K.I.S.S.

Don't get hung up on information overload. I think for people new to exercise, the simpler, the better.

If you want to lose weight, a lot of people recommend 30-60 minutes sessions but intensity (which is obviously relative to your current level of fitness) is more important than how long you exercise.

Don't try to get fancy with body part splits and assorted isolation exercises. For one thing, lots of people are confused about what exercises work which body parts. Even more important is that total body workouts consisting of primarily compound exercises will burn more calories. Plus, you can't truly isolate muscles anyway.

My advice to workout newbies is to get moving with challenging, no-fuss total body workouts, experience the benefits and results of regular exercise and THEN start debating / experimenting with body part splits, isolation exercises, etc. if they really feel the need.