Hi Cecil and welcome to Wikitree :)
As Betty and T. Cassidy have already said, you start with yourself, add your parents and close family and build from there.
I know getting started can be a little overwhelming, so if you look to the top right of the page you will see 4 tabs, which turn into drop down menus. The 4th tab which is the help tab has many sections covering a variety of topics which you may need help with at some point. The Help Index link there is a good place to start. Open up the letter G there and scroll down to Genealogy..getting started. All you need to know to get on the first step is there. You have already made a big step by finding this G2G which is the hub of communication and friendly help.
If you don't understand something or get stuck please do come and ask right here on G2G. Someone will jump in and try and help you. Just remember to give full information in the text of the question :)
Good luck and happy researching