Basic , where to start.
Write down everything you already know about yourself, your parents, and your grandparents. Once you have it written down, you may realise that you do not know much, but get it down on paper so that you have a starting place.
Gather records and information about your birth, marriage and so forth. Look for photographs, documents, old letters, diaries, newspaper clippings, and family Bibles.
Also ask your parents, grandparents, Aunts and Uncles about such items, you never know they might have already started researching.