There are plenty of Jacque Cossart descendants who already have profiles in WikiTree. (I know this because I've proposed merges for a number of duplicates I've found.) Therefore, chances are good that many of the people you have data for are already "here." This means your best bet is to start by searching for existing profiles. For starters, see the Cossart and Cozart surname lists. (Those are links to lists sorted in chronological order; I find that sorting helpful for seeing how a family is covered over time.)
Add your new information and sources to the existing profiles you find, and once you determine that a particular child or spouse hasn't been created yet, add that child as a member of whatever family is already here. Most of us find that hand-adding profiles works out better than uploading gedcoms, particularly for families that are already partially here. (And since your data isn't currently in a gedcom format, there's no particular value in converting it.)
