Welcome to WikiTree, Richard. Have you read about what you will need to do after importing your GEDCOM? If you are not interested in doing this work, you may want to reconsider importing it, or consider splitting your GEDCOM into a smaller file and importing that first to see what effort will be required to clean up the files. You may also want to read a previous G2G post about the angst of importing a GEDCOM.
It's great to start with your parents notes, which likely come from their personal knowledge of relatives they knew, and perhaps from obituaries or other research. Confirming them with "internet findings" is rather vague. Do you mean from other compiled genealogies on Ancestry, My Heritage, Geni, or other similar sites? If so, these may be either more or less accurate than your parents notes. If you mean that you have found online records, such as obituaries, census records, birth records, marriage records, etc., those could be considered primary resources. You will want to list each specific source in each profile. You will want to read the WikiTree page about Sources.