Find a hill which is short enough for you to walk, jog or run comfortably but long enough to be challenging! (Perhaps 25m to 100m depending on fitness levels and the challenge you want!).
First attempt, jog up the hill to feel the gradient and the challenge. Now decide whether to repeat 3, 4, 5 or 6 times (more if you want). Time yourself from the start to the end. Record your time. In future repetitiions you are going to continualy try to beat that time or to keep it as consistent as you can. After each repetition, rest for 1 minute or until your breathing is comfortable to continue again.
Let me know how you get on. Repeat twice a week and add to this a walk, jog / run for 15 – 30 minutes. Enjoy!