Tom,
This might help:
https://www.wikitree.com/wiki/Help:Sources
And, you can always reach out to a Mentor for some help.
I like to use the RootsSearch tool, from the profile menu Research pulldown to search on FamilySearch. You have to provide your WikiTree login (just once). Once there I will search with the default values, then sometimes remove things like the wife's or mother's maiden name. When you find a source on FamilySearch, you can cut/paste the section under Citing this Record and place it as * paste here under the == Sources == heading.
For example, I tried this for Amanda's father. The first thing that was found was his marriage:
"Indiana Marriages, 1811-2007," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:XXVM-CVM : 10 February 2018), James W Timmons and Martha Jane Olinger, 01 Aug 1851; citing Carroll, Indiana, United States, Marriage Registration, Indiana Commission on Public Records, Indianapolis; FHL microfilm 004203304.
and that might lead you to other things like census records (be sure to check it is the correct family) and items that will help you fill in the birth/death locations that will help with your searches.