Hi Margaret, Welcome to Wikitree!
I'll try to help you.
If you are entering a profile for the first time, in the blank space, you will type:
== Biography ==
You can copy the information from Find a Grave and edit it or compose what you think is important to know about the person
== Source ==
* URL: [paste the URL in brackets]
* Detail and Reference from Source like Year, example (this is old school but you can see what you're doing :
* Year: 1900; Census Place: Greenville, Outsgamie, Wisconsin...
But if you are working on a profile that already has sources, enter your information at the end of the list. Delete links (colored letters and numbers) only if they are disabled or don't take you to any information.
I'm not the best one to answer this, but everyone's working on projects and it may take a bit to get you a better answer.
Feel free to email and I'll answer as best as I can.