Carol, when you check a match and accept it, that person is already on WikiTree, so you won't be adding them at all. If you did, that would create a duplicate and WikiTree only wants one profile for any person because there's only one humongous tree which we all share.
You will be eventually adding any individuals for whom you rejected matches or who had no matches. You have to check EVERY individual in your GEDCOM with a match, which means accepting or rejecting EVERY potential match before you get the ADD buttons to create a profile for anyone. When you get your ADD buttons, you will still add each person individually--they are not all added at once. You can decided at that time to add "family groups", but it will still be a one-by-one process. By the way, each profile you create in this way will contain "GEDCOM junk" which will need to be cleaned up/removed and you may have to reformat your sources to make them useful.