Changes I could make

I realize that I should stretch before I exercise.  I tend to stretch after I exercise.  I would like to exercise more but not exercise out a bad diet.  This is what I have been doing.  It is great to exercise but I am not losing any weight.  I am trying but I am not doing a great job.  I would like to not only look better and feel better due to exercise, but eat better as well.  I did lunges, squats, and also walked for 13 minutes.  It was a pretty decent workout, but there is no such thing as working out a bad diet.  That is what I am guilty of.