I kept it simple and those starting should also. If you are a runner or looking to some cardio start with jogging and running drills and repeat. Today I did 20 sets of push ups with both running drills, 2 of them and then a third group of just strides and push ups for 300 push ups in total. I am hitting it 3 days a week to start then 5.
Keep your start if off a layof to 3 days at around 30 minutes total:).