If you are new to researching your family tree than you can find books in the library on the subject and you can use the internet for help. Just google, starting your family tree, or starting genealogy, or something like that.

Best wishes in your research.

If able, talk to your father and any other living relatives who can give you names/dates/stories. Then go from there. If you are close to a library, they may be able to help. Otherwise, once you have as much information as you can, work on backing it up with birth, death, marriage certificates which will then give you more information to go on with. Join some online forums and ask questions. I google a LOT :) However, the most important bit of advice I can give is try and find three different means of confirming a relative is yours before you claim them. I once had to re-do around twenty people in my tree because I didn't triple check that one of them was actually related. Good luck and best wishes in your research!