I personally thought of doing this when i have the free time and if i get that free time. My mind seem to be pre-occupied on other things - random thinking...
First and foremost, find a spot in your garden that you wish to setup your soon-to-be garden. Start with a small area first. You wouldn't want to get overwhelmed with such a big garden.
As soon as you find that small area for your garden, research on the plants you can easily nurture that suites your area's climate. Remember, not all plants can grow in your country's climate. You might want to start with something easy to grow. Like what they always say: You reap what you sow.
Try to visualize the garden you want to create, if possible, sketch it down so you will have a guideline to your garden. You will be able to bugdet the necessary tools, soil, seeds and pots you wish to be in your garden. If you don't want to start from nurturing seeds, try dropping by those who sells seedlings and ask their advices on how to take care of the plants you wish to grow.
Sounds easy.. but it takes patience to start a garden and everyday you have to watch out for insects that could harm your plants...
Good luck to those who wish to persue this...