I recommend doing a full body routine 3 days a week. Let's say Monday, Wednesday and Friday. I keep things simple. I pick one exercise for each muscle group and do 3 sets of 10 reps for it.
I warm up for 5 minutes, do 3 sets of 10 reps of one exercise per muscle group, then I do 10 minutes cardio and a cool down/stretch.
On Tues/Thurs/Sat I'll do 45 minutes medium intensity cardio. Sunday I'll rest or take a long leisurely walk.
Hopefully that'll get you started. As you progress, yu'll want to change things ups and go to a higher intensity program. But the above is a pretty solid beginning routine.