If what you have to add is using either internet trees or books written by famiily members those are not valid sources for pre-1700 or pre-1500 profiles.
You can use them as clues but need to find something that validates the information. Things that work are:
If you find them birth, marriage or death records but often they are hard to find.
Court records (sheriff records)
Some town have a town history that may name some of the people in the town. These can be used with an asterisk... check the known frauds section of the link I give you below.
I wish it was easier but it is not.
This is a list of sources that you can use
The reason we don't use trees or family written book is that there was a style to try to connect your family to a ruling or noble family and a lot of bad genealogy took place. Also generally there are more than one person with the same name living in the same area in the same time period because Grandpa was say John, one of his sons was John, and 3 of his grandsons from 3 different sons are all John... so now you have 5 of them living in the same area at the same time... And often families could be bigger than that... and in my scenario the descendants are all sharing the same DNA from Grandpa..