Warmup is only important for activities that will cause your body to stress fast (sprints, soccer, etc). But is not needed when doing longer endurance type activities.
Cool down is not same as stretching.
Stretching should always be done, and there are tons of possibilities here. Check YouTube if you need a routine, but try to mix up routine every other week.
Cool down should be a light activity that allows muscles to slowly relax. Again more important for shorter activities and sports games. Try a slow jog for 5-10 mins, or some other light workout that mimics muscles used in your workout, but done slower and lighter and for only a few mins.