Those fancy family fan charts look beautiful, but when you are starting out, can be intimidating.
You don't need a pretty diagram or a fancy program to start your family tree. When I began, I literally took a sheet of college-rule lined notebook paper. I wrote my information and drew an arrow to the left and an arrow to the right. Then I wrote what I knew about my parents. I then draw two arrows for each of them and wrote out what I knew about my grandparents. I continued this as far back as I could.
The next step is crucial!! Call up the people in your family and ask questions! You will have gaps in information or even in generations. You might be shocked to find out that your sister knows how your grandparents met due to a school project or that your mother has information on further generations back.
Really want to stretch your knowledge? Create a survey of sorts with questions about a person and their relatives and then send it out to all living relatives! Don't forget those cousins that live 1000 miles away!
It truly is as simple as this to get started on your family tree. If you enjoy this and get hooked, then look into how to organize your information.