Start with setting the goals. The goals for your eventual fitness level as well as how much time you can afford to put in everyday or every week. This will allow you to have a road map to where you want to be and you can figure out the time you will need to get to that objective.
Chalk Down Details
Once you have the goals understood, the next thing to do is take a planner and mark the times and workouts you are looking to do. You can also make on by hand with color coding or make one on the computer. Make sure that you keep it realistic and make sure that the exercises and timings are both within your ability.
Keep a number of options in your calendar. Repeating the same exercises over and over can make you feel bored and you can lose interest. Take time to add exercises of various types and also add something that you find fun.
Be flexible, if you miss a workout or do not feel like doing one, you should do it on another time or do another exercise that you feel like doing. This will keep you on track and instead of losing the plot; you will be able to attain some impact from even a lesser intensity workout.
Make sure that you keep a track of the exercises and the time that you have spent doing them. Many smart phone apps allow you to track the number of calories you have burnt in a workout and help you know the time you have been engaged in exercise. You can jot down those numbers on the calendar and compare notes every day.
Keep yourself motivated and be kind to you when you do well. You can grab some new clothing or shoes once you reach a mini milestone. This will keep you going further which is the purpose of the whole exercise.