Hi Michelle, Wikitree emphasises finding sources. Whether they are from sites like familysearch.com, books, or the family bible , they are all sources. The difference is that user uploaded trees on other sites are in themselves not sources- they might cite actual sources or give you ideas where to look.
If the source is family records, it is best to name them specifically. You don’t have to scan them in, just note that you possess them.
When it comes to profiles before 1700 the requirement is stricter and pre 1500 is somewhat specialised.
You will be surprised how quickly you will become used to this site and I have found everyone is helpful