Hi Jim! Welcome to the one world WikiTree. You can find out about GedCom imports here: https://www.wikitree.com/wiki/Help:GEDCOM
WikiTree is a one world wide family tree. You add your family twigs to the WikiTree and try to connect your twigs to surname branches. Eventually the branches connect to the WikiTree trunk. The goal is to have one leaf, called a profile, on the WikiTree for everyone that ever lived that can be documented. If two or more leaves are created for the same person, they must be merged back to the lowest ID number with the correct surname spelling.
Your contributions of your family twigs are gifts to the WikiTree community. They are donated with the knowledge that others will contribute to your profiles with biographies, sources, pictures, documents and other information to improve each donated profile. Through collaboration, each of us donating our time and expertise in our areas of interest, we are improving the the 15 million+ profiles on the WikiTree.