Advice on starting an NPO

Hi I woke up this morning in Johannesburg among all the hustle, bustle and rain. On my way to work I was confronted with a woman and her baby begging at a robot for money. Upon closer inspection, she informed me that she has no home, money or food. In an attempt to help I put her in my car and got her breakfast. But thats not going to keep her full for long... I want to make a difference in our country, to the people of our country. I'd like to start a non profit organisation but I have no idea were to start. Can anyone offer me advice?